TEXT    BOOK 


OF 


MILK    HYGIENE 


BY 


DR.  WILLIAM  ERNST 

Official  Veterinarian  and  Director  of  the  Royal  Milk  Control  Station  at  Munich 


AUTHORIZED   TRANSLATION  WITH   ANNOTATIONS   AND   REVISIONS 


BY 


DR.  JOHN  R.  MOHLER,  A.  M.,  V.  M.  D. 

Chief  of  Pathological  Division,    United  States  Bureau  of  Animal  Industry 


AND 


DR.   ADOLPH  EICHHORN,  D.  V.  S. 

Senior  Bacteriologist,  Pathological  Division,  United  States  Bureau  of  Animal  Industry 

With  29  Illustrations  and  5  Colored  Plates 


CHICAGO,  U.  S.  A. 
ALEXANDER    EGER 

PUBLISHER 
1914 


COPYRIGHTED  AT  WASHINGTON,  D.  C. 

BY 

ALEXANDER    EGER 
1914 


;^ 


COMPOSITION.    ELECTROTYPINO.    PRINTING 
AND    BINDING    BY   THE 

W.  B.  CONKEY  COMPANY 
HAMMOND.  INDIANA 


Table  of  Contents 


PAGE 

Translator 's  Preface   vii 

Author 's  Preface   ix 

CHAPTER  I. 
Anatomy.  Pathology  and  Histology  of  the  Mammary  Gland 1 

CHAPTER  II. 
Physiology  of  Lactation  and  Characteristics  of  Milk  in  General 16 

CHAPTER  III. 
Microscopy  of  Milk  in  General 24 

CHAPTER  IV. 
Composition  of  Milk  and  Its  Biological,  Chemical  and  Physical  Characteristics     32 

CHAPTER  V. 
Procurement  of  Cow 's  Milk 58 

CHAPTER  VI. 
Internal  Influences  on  the  Character  of  Milk 62 

CHAPTER  VII. 
External  Influences  which   Act  Upon  Milk 132 

CHAPTER  VIII. 
Bacteria  in  Market  Milk ;  Their  Origin  and  Action 152 

CHAPTER    IX. 
Milk  Control   203 

CHAPTER  X. 
Milk  Inspection 211 

CHAPTER  XI. 
Fundamental  Principles  of  Legislative  Milk  Control.  ....*... 233 


Translator's  Preface 


THE  importance  of  food  hygiene  in  the  protection  and  preser- 
vation of  public  health  is  now  generally  recognized.     Milk 
constitutes  one  of  the  most  important  foods  for  the  human 
race,  and  since  its  composition  and  wholesomeness  are  entirely 
dependent  upon  its  proper  handling,  the  necessity  for  a  strict 
supervision  and  control  is  obvious. 

The  problem  of  milk  hygiene  is  very  complex  and  must  embody 
all  phases  of  milk  control  from  the  time  the  milk  is  produced  until 
it  reaches  the  consumer.  In  all  stages  it  may  be  subjected  to 
wilful  adulteration  and  to  contamination  with  injurious  and  ob- 
noxious substances.  Furthermore,  the  danger  threatens  this  most 
valuable  food  not  only  from  outside  sources  but  also  from  internal 
influences,  as  the  milk  may  leave  the  animal  in  the  condition  of  a 
dangerous  product,  a  carrier  of  pathogenic  microbes.  Various 
kinds  of  infection  of  the  udder  are  frequently  important  factors 
in  the  contamination  of  milk,  which  would  render  it  dangerous  to 
the  consumers.  Thus  in  recent  years  numerous  outbreaks  of  in- 
fectious sore  throats  have  been  caused  by  such  conditions.  It  is 
therefore  apparent  that  in  the  proper  control  of  the  milk  supply  it 
is  necessary  to  be  familiar  with  all  conditions  which  may  be  re- 
sponsible for  an  injurious  or  unwholesome  product.  The  subject 
is  one  in  which  every  sanitarian  should  be  thoroughly  qualified. 

Although  there  are  numerous  splendid  publications  available 
on  this  subject,  they  are  either  too  voluminous  to  be  used  as  text- 
books or  they  fail  to  contain  the  more  recent  very  important  devel- 
opments made  in  this  branch  of  public  hygiene.  The  excellent 
German  publication  of  Dr.  Ernst  entitled  "Milk  Hygiene"  meets 
the  requirement  of  a  concise,  up-to-date  work  on  that  subject,  and 
it  is  with  pleasure  that  in  response  to  requests  from  various  sources 
we  have  accepted  the  preparation  of  an  English  edition  of  this 
publication.  We  did  not  lose  sight  of  the  fact  that  it  should  meet 
with  the  conditions  prevailing  in  this  country  and  accordingly  we 


Translator's  Preface, 


have  included  much  valuable  information  from  the  reports  of  the 
various  Milk  Commissions,  and  other  sources.  For  this  reason 
Chapter  X  dealing  with  German  laws  and  regulations  has  been 
replaced  by  Chapter  XI  which  deals  solely  with  the  conditions  and 
standards  existing  in  this  country. 

We  cannot  refrain  from  expressing  our  sincere  thanks  to  Dr. 
H.  J.  Washburn  for  his  most  valued  suggestions  and  assistance  in 
proofreading  the  manuscript ;  also  to  the  publisher,  Mr.  Alexander 
Eger,  for  his  interest  and  courtesy  during  the  preparation  of  this 
volume. 

JOHN  E.  MOHLER, 
ADOLPH  EICHHOBN. 

Washington,  D.  C.,  July  1,  1914. 


Author's  Preface 


THE  increased  importance  of  milk  as  human  food  demands 
more  and  more  the  application  of  modern  accomplishments 
and  experiences  achieved  by  science  and  practice,  in  order 
to  elevate  the  milk  industry  to  the  desired  high  standard. 

The  principal  stress  must  be  laid  upon  production,  which  con- 
stitutes a  special  field  of  the  milk  industry,  and  which  is  most 
generally  in  need  of  elevation  and  improvement.  The  product 
will  be  without  reproach  only  when  the  conditions  of  production 
correspond  to  the  value  of  this  food. 

In  the  field  of  production,  veterinarians  are  the  proper  ex- 
perts who  must  stand  by  the  side  of  the  producers  and  give  them 
the  necessary  advice  and  instruction.  Only  by  the  active  and  ex- 
pert aid  of  veterinarians  can  it  be  hoped  to  improve  the  good-will 
of  the  producers ;  provided,  at  the  same  time,  other  points  of  milk 
hygiene  which  possess  bad  features — in  spite  of  the  active  progress 
of  milk  control  and  sanitary  methods  which  have  been  noted  for 
many  decades — also  receive  proper  attention. 

In  order  to  be  able  to  offer  expert  advice  a  thorough  knowl- 
edge of  milk,  its  formation,  procurement  and  characteristics,  is 
necessary;  likewise,  a  knowledge  of  conditions  which  have  an  in- 
fluence upon  milk  while  still  in  the  animal  body,  and  the  factors 
which  change  this  food  after  its  procurement.  These  points  have 
received  the  principal  consideration  in  the  following  chapters. 

In  the  plan  which  I  have  followed,  those  questions  which  treat 
of  the  judgment  of  milk  as  human  food  in  relation  to  its  chemical 
contents,  were  given  less  prominence.  Certain  points  of  this  sub- 
ject have  been  mentioned  only  to  an  extent  that  was  considered 
advisable  for  the  general  comprehension  of  the  subject.  More 
specific  questions,  as  for  instance,  the  preparation  of  certain  milk 
mixtures  for  the  feeding  of  infants,  the  advantages  and  disadvan- 
tages of  feeding  cows'  milk  to  infants,  the  action  of  a  milk  diet 
in  the  treatment  of  adults,  etc.,  are  subjects  for  the  physician.  A 


Author's  Preface. 


special  chapter  on  the  preparation  of  infants'  milk,  or  certified 
milk,  has  been  omitted,  since  the  sanitarian  can  not  make  any 
distinction  in  his  judgment  of  milk  as  food,  but  must  remember 
that  milk  which  is  consumed  by  children  of  the  masses  should  also 
come  up  to  the  requirements  established  for  any  food  product 
from  a  hygienic  standpoint. 

The  chemical  and  physical  properties  of  milk  are  only  dis- 
cussed to  an  extent  deemed  necessary  to  instruct  the  veterinary 
experts  in  court  cases  in  judging  physiological,  pathological  and 
external  influences.  Since  the  chemical  examination  of  milk  should 
be  placed  in  the  hands  of  the  food  chemist,  I  have  eliminated  the 
analytical  examination  of  milk  and  the  examination  for  preserva- 
tives. For  this  information  I  would  recommend  the  numerous 
publications  which  have  appeared  during  recent  times,  as  for  in- 
stance, the  works  of  Grimmer  and  Sommerfeld,  Teichert,  Utz  and 
Barthel.  Only  those  methods  have  been  described  which  may  be 
undertaken  by  the  veterinarian  and  which  are  sufficient  for  a 
thorough  preliminary  test  of  milk  for  adulterations. 

The  illustrations  are  taken  partly  from  the  known  works  of 
my  previous  teacher,  Professor  Dr.  med.  Th.  Kitt  (Pathological 
Anatomy)  and  from  Friedberger  and  Frohner's  Methods  of  Clini- 
cal Examination ;  some  were  drawn  by  myself.  The  illustrations 
of  apparatuses  have  been  avoided,  as  they  appear  in  all  commercial 
catalogues. 

In  dividing  the  subject  into  individual  chapters  repetitions, 
of  course,  could  not  be  avoided. 

With  the  preparation  of  this  small  work  I  desire  to  show  to 
my  colleagues  the  road  which  they  must  follow  in  order  to  cooper- 
ate from  a  milk  inspection  standpoint  in  accordance  with  the  call 
made  upon  their  profession. 

A  difficult  point  of  milk  hygiene  lies  in  the  changing  conditions 
of  production  and  not  in  the  control  of  milk  consumption  or  in  the 
supervision  of  milk  transportation. 

W.  ERNST. 

Munich,  January,  1913. 


CHAPTER  I. 

ANATOMY,  PATHOLOGY  AND  HISTOLOGY  OF  THE 
MAMMARY  GLAND. 

Development  and  Gross  Anatomical  Structure. 

In  the  lowest  form  of  mammalian  life  a  group  of  glandular 
ducts  becomes  differentiated  from  the  glands  of  the  skin  in  the 
median  abdominal  region.  These  ducts  exude  their  lacteal  secre- 
tions upon  tufts  of  hair  of  the  mammary  region,  from  which  it  is 
either  licked  or  sucked  by  the  young  (duckbill,  Ornithorhynchus 
paradoxus). 

One  of  the  land  duckbills,  the  spiny  anteater  (Echidna  hys- 
trix),  has  lacteal  ducts  opening  within  an  abdominal  pouch 
formed  by  a  fold  of  skin  of  the  mammary  region  in  the  shape  of  a 
pocket,  in  which  the  young  are  protected  and  nourished  during 
their  development.  This  abdominal  pouch  is  not  identical  with  the 
tegumentary  wall  from  which  is  developed  the  teats  of  higher 
mammals,  but  it  may  be  taken  as  the  point  of  origin  of  the  different 
forms  of  teats.  In  higher  marsupial  animals  the  glandular  ducts 
are  united  into  a  complex  gland  with  teats  which  constitute  the 
orifices  of  the  confluent  lacteal  ducts.  In  other  still  higher  species 
the  most  varied  kinds  of  gland  structures  are  observed  with 
various  forms  of  teat  development. 

Among  the  higher  mammalian  forms  the  evolution  of  these 
anatomical  structures  may  be  followed  during  embryonic  life. 

On  both  sides  of  the  body,  between  the  anterior  limb-bud  and  the  inguinal  fold, 
the  milk-ridge  develops  from  a  linear  thickening  of  the  ectoblast  in  the  form  of  a  ledge- 
like  elevation  of  the  epidermis.  Along  this  milk-ridge  a  series  of  at  first  spindle-shaped, 
then  round  enlargements  appear,  which  are  separated  by  absorption  of  the  intervening 
portions  of  the  ridge.  These  enlargements  consist  of  masses  of  epithelial  cells,  which 
correspond  to  the  anlage,  primordium  or  point  of  origin  of  the  true  mammary  gland  of 
the  lowest  mammalia.  This  anlage  sinks  into  the  underlying  mesoblastic  tissue  and 
becomes  surrounded  by  a  proliferating  integument,  which  forms  an  investment  for  the 
growing  epithelial  mass.  From  this  mammary  envelope  which  becomes  more  or  less  flat- 
tended  the  fibrous  and  muscular  tissue  of  the  areola  and  teat  are  derived.  At  its  base, 
solid  epithelial  sprouts  grow  out  from  the  sides  of  the  conical  epidermal  plug,  later  be- 
coming the  lactiferous  ducts,  while  the  club-shaped  thickened  extremities  in  the  further 
course  of  their  development,  form  the  milk  sinus.  Subsequently,  the  central  part  of  the 
ectoblastic  ingrowth  undergoes  degeneration  and  what  at  first  was  an  elevation,  now  be- 

1 


Pathology,  and  Histology  of  the  Mammary  Gland. 


comes  a  depression.     From  the  middle  of  this  depressed  area  there  appears  an  elevation 
that  later  becomes  the  teat. 

In  cattle  a  single  excretory  canal  enters  from  the  bottom  of 
the  mammary  envelope  (point  of  the  teat),  into  the  tissue  (the 
milk  duct),  the  end  of  which,  the  milk  cistern,  breaks  up  into  the 
secondary  lactiferous  ducts.  The  lower  opening  of  the  teat  con- 
tains unstriped  muscle  fibres  which  act  as  a  sphincter  to  prevent 
the  escape  of  milk.  (Meckel,  Kolliker,  Langer,  Bonnet,  Profe, 
Schwalbe,  Huss,  Gegenbauer,  Klaatsch.) 

According  to  the  number  of  the  glandular  organs  there  are 
distinguished  the  oligomasts  and  the  polymasts.  Cows  are  nor- 
mally tetramasts,  and  usually  possess  four  distinctly  separated 
glandular  masses,  commonly  termed  the  quarters,  from  each  of 
which  protrudes  a  long  teat.  The  four  quarters  are  united  to- 
gether in  pairs  and  are  arranged  symmetrically.  Between  their 
bases  and  the  yellow  abdominal  fascia  they  have  a  rich  layer  of  fat. 

The  udder  is  attached  along  the  linea  alba  to  the  yellow  abdominal  fascia,  and  to 
the  tendons  of  the  abdominal  muscles,  by  two  layers  of  elastic  tissue,  the  suspensory  liga- 
ment (ligamentum  suspense rium  mammarum)  which  penetrates  the  udder  between  the 
two  halves. 

Although  the  quarters  situated  on  one  side  show  no  visible 
anatomical  separation,  injection  tests  with  colored  gelatin,  and  ob- 
servations in  cases  of  inflammation  of  the  udder  in  natural  and 
artificial  infections  have  proven  that  the  secretory  canal  systems 
of  the  anterior  and  posterior  quarters  are  separated  in  the  same 
way  as  those  of  the  opposite  quarters. 

These  canal  systems  collect  into  excretory  ducts  and  terminal 
tubules  and  finally  empty  into  the  milk  cistern,  which  in  its  upper 
part  is  greatly  dilated  and  in  its  lower  part  is  more  constricted. 
Each  quarter  possesses  a  teat  (6  to  10  cm.  in  length)  from  the  milk 
sinus  of  which,  the  duct  of  the  teat  (ductus  lactifera)  of  about  8 
mm.  in  length,  passes  to  the  outside.  The  entire  udder  is  covered 
by  fine,  slightly  hairy  skin,  which  extends  posteriorly  and  supe- 
riorly into  the  escutcheon  or  so-called  milk  mirror. 

The  size  of  the  udder  varies  in  the  different  breeds  and  indi- 
viduals. 

In  the  sheep  and  the  goat  there  are  two  milk  glands,  each  possessing  a  teat  which 
stands  out  in  a  divergent  direction  from  the  one  opposite.  Each  teat  has  one  excretory 
duct.  While  the  teats  of  the  sheep  are  finely  haired,  those  of  the  goat  are  hairless. 

The  blood  vessels  of  the  udder  are  derived  from  the  branches 
of  the  external  pudic  artery  and  anastomose  with  the  various 
venous  branches,  through  which  the  blood  flows  posteriorly 
through  the  perineal  vein  into  the  internal  pudic  vein  and  finally 
into  the  obturator  vein.  The  greatest  part  of  the  venous  blood 
flows  laterally  into  the  external  pudic  vein  and  anteriorly  into  the 
subcutaneous  abdominal  vein,  which  forms  the  immediate  continu- 
ation of  the  external  pudic  vein  and  which  is  known  as  the  milk 


Pathological  Anatomy  of  the  Udder. 


vein.  It  runs  bilaterally  of  the  median  line,  penetrates  posteriorly 
and  laterally  to  the  xiphoid  cartilage  of  the  breast  bone  into  the 
deeper  parts  and  then  empties  into  the  internal  thoracic  vein. 

The  lymph  vessels  which  are  very  numerous  enter  two  large 
lymph  glands  which  lie  bilaterally  in  a  depression  at  the  posterio- 
superior  portion  of  the  udder  and  are  known  as  the  supramam- 
mary  lymph  glands.  The  lymph  passes  thence  to  the  lumbar 
glands  and  into  the  thoracic  duct. 

The  nerves  originate  from  the  lumbar  plexus.  The  udder  is 
supplied  by  the  internal  branch  of  the  ilio-hypogastric  nerve,  the 
external  branch  of  the  lumbo-inguinal  nerve,  and  the  external 
spermatic  nerve.  In  the  goat  the  external  spermatic  nerve  divides 
in  the  abdominal  cavity  into  three  branches,  of  which  the  median 
and  the  caudal  branches  pass  through  the  inguinal  ring  to  the 
udder.  The  cephalic  branch  passes  to  the  abdominal  muscles. 
The  caudal  branch  (inferior)  is  purely  a  vascular  branch.  The 
median  branch  passes  to  the  udder,  and  ramifies  to  the  milk  ducts 
and  the  teats. 

Pathological  Anatomy  of  the  Udder. 

Of  the  pathological  processes  which  are  of  importance  from 
a  practical  standpoint,  the  inflammations  and  changes  which  have 
more  or  less  influence  on  the  quality  of  the  milk  are  of  special  in- 
terest. The  other  anomalies  will  be  mentioned  only  briefly. 

Not  infrequently  there  may  be  present  in  cows  supernumerary 
teats,  or  supernumerary  milk  glands,  which  may  be  considered  as 
a  reversion  to  early  stages  in  the  evolution  of  cattle.  Usually  two 
rudimentary  formations  occur  which  are  generally  situated  behind 
the  posterior  normal  glands  and  normal  teats.  These  may  at  times 
yield  milk  (Burkart,  Dauberton).  These  accessory  glands  may 
also  occur  between  the  normal  teats.  In  several  instances  as  many 
as  four  supernumerary  teats  were  observed. 

If  the  udder  is  abnormally  small  in  its  development  or  is  en- 
tirely absent,  it  constitutes  hypoplasia  or  aplasia  of  the  udder. 
According  to  Bosetti  the  absence  of  the  mammary  gland  was  ob- 
served in  a  cow  two  and  a  half  years  old.  Although  there  were 
four  small  teats  on  the  skin,  no  milk  was  secreted  even  after  the 
birth  of  a  healthy  calf.  The  milk  veins  were  well  developed  on 
both  sides. 

The  opposite  condition,  hypertrophy  of  the  udder,  with  or 
without  secretion,  is  most  conspicuous  in  male  animals.  Pusch  ob- 
served a  buck  which  produced  70  gm.  of  colostrum-like  milk  daily, 
and  which  possessed  nipples  7  to  9  cm.  in  length.  Grurlt  has  re- 
ported that  the  udder  of  a  steer  was  as  strongly  developed  as  in 
a  cow,  and  produced  daily  iy2  liters  of  secretion. 

It  is  known  that  newly  born  kids  and  suckling  colts  occasion- 
ally secrete  milk  for  several  days  (Gurlt,  Martin,  Hess,  Ibel). 

Schmidt,  of  Dresden,  reported  a  giant  udder  with  an  entirely 


Anatomy,  Pathology  and  Histology  of  the  Mammary  Gland. 


normal  milk  secretion,  (16  liters).  A  functional  hyperemia  in 
the  beginning  of  the  lactation  period  increased  the  four  quarters 
uniformly  to  such  an  extent  that  a  day  after  parturition  the  udder 
touched  the  .ground  with  its  central  surfaces. 

Before  and  after  parturition  an  abnormal  amount  of  hy- 
peremia occurs  physiologically  in  the  udder  (hyperemia  conges- 
tiva).  In  inflammations  the  same  condition  may  be  present,  the 
capillaries  are  abnormally  dilated,  and  greatly  distended  with 
blood.  This  condition  may  result  in  the  exuding  of  fluid  and  the 
solid  constituents  of  blood.  These  are  known  as  capillary  hem- 
orrhages. In  larger  extensions  of  these  hemorrhages  they  are 
spoken  of  as  suggilations,  and  when  the  blood  is  contained  in  a 
sac-like  cavity  or  swelling  it  is  known  as  hematoma  uberis. 

If  in  the  congestive  hyperemia  the  fluid  constituents  of  the 
blood  pass  into  the  tissue  of  the  udder,  it  results  in  edema  of  the 
udder.  The  same  condition  may  develop  as  a  result  of  hydremia, 
as  for  instance  after  changing  from  dry  to  sloppy  foods  (Bang), 
or  as  a  result  of  multiple  emboli  of  the  blood  vessels,  or  from  a 
varicose  condition  of  the  veins  of  the  udder. 

Edema  of  the  udder  manifests  itself  as  a  soft  or  tense  swelling  of  the  tissue,  which 
retains  the  impression  of  the  finger.  While  the  teats  usually  remain  normal  on  account 
of  their  slight  but  dense  connective  tissue,  quantities  of  fluid  collect  in  the  front  of  the 
udder  and  between  its  glandular  substance  and  the  skin. 

The  edema  frequently  extends  posteriorly  to  the  udder  and  up  to  the  vulva.  In- 
fections of  wounds  with  the  bacillus  of  malignant  edema  may  result  in  edema  of  the 
udder. 

To  those  engaged  in  milk  hygiene  the  most  important  of  all 
pathological  conditions  of  the  udder  are  the  inflammations  which 
result  from  a  reaction  of  the  glandular  tissue  to  any  inflam- 
matory irritant.  In  most  instances  the  inflammations  of  the  udder 
are  produced  by  microbian  infections  of  various  kinds,  particularly 
by  poly-bacterial  infections.  The  bacteria  penetrate  the  udder 
either  by  way  of  the  blood  circulation  or  from  the  outside  through 
the  orifices  of  the  milk  ducts.  In  such  cases  it  is  spoken  of  as  a 
hematogenic  or  galactogenic  mode  of  infection.  If  the  infection 
results  from  a  mixture  of  bacteria,  and  is  not  caused  by  one  kind 
alone,  the  affection  is  a  mixed  infection.  The  infection  may  result 
from  traumatic  conditions  when  injuries  extending  into  the  paren- 
chyma of  the  glands  make  the  infection  possible,  or  from  galactif- 
erous-traumatic  causes  when  the  infectious  material  enters  the 
milk  cisterns  upon  milking  tubes  or  straws.  The  infection  may 
take  place  also  through  simple  contact  of  the  orifice  of  the  teat 
with  the  infectious  material.  Thus  the  different  forms  of  mastitis, 
the  peracute,  acute  or  chronic  inflammations  of  the  udder  may 
arise,  depending  upon  the  character  of  the  infectious  material  and 
upon  special  accessory  conditions. 

The  possibility  of  galactiferous  infection  was  first  experimentally  proven  by  Frank. 
The  character  and  the  varieties  of  inflammations  of  the  udder  were  further  established 
.by  the  work  of  Kitt,  Nocard  and  Mollereau,  Lucet,  Bang,  Hess  and  Borgeaud,  Guillebeau. 
Zschokke,  Sven  Wall,  and  others. 


Pathological  Anatomy  of  the  Udder. 


The  principal  producers  of  mastitis  are  the  colon-paratyphoid 
group,  staphylococci,  streptococci,  Bacillus  pyogenes  bovis,  Bacillus 
tuberculosis,  and  the  actinomyces. 

Colon  infection  and  severe  mixed  infections  usually  result 
from  galactiferous  contact,  or  after  the  introduction  of  milking 
tubes,  straws,  quills,  cat-guts,  and  hairpins.  Highly  acute,  inflam- 
matory conditions  develop  in  the  affected  quarters,  whether  af- 
fected throughout  or  only  partially  with  parenchymatous  mas- 
titis. Hot,  painful  swellings  of  the  quarters,  with  collateral  edema 

Fig.  1. 


Acute    inflammation    of    the    right    forequarter   with    collateral    edema. 

(After  Kitt.) 

of  the  surrounding  tissues,  are  the  associating  symptoms  of  this 
form  of  inflammation,  which  either  results  in  recovery  with  atrophy 
of  the  affected  parts  of  the  udder,  or  with  regeneration  of 
the  epithelia  destroyed  by  the  disease  or  on  the  other  hand  the  di- 
sease becomes  chronic  and  may  even  terminate  with  complete  gan- 
grenous and  ichorous  destruction  of  the  affected  part  of  the  udder. 

In  the  infectious  forms  of  mastitis  the  supramammary  lymph  glands  may  swell  to 
fist-sized  nodes. 

If  the  process  becomes  chronic  a  suppurative  softening  of  the 
affected  parts  of  the  tissue,  or  a  suppurative  demarcation  of  ne- 
crotic  parts  of  the  tissue  results.  These  conditions  are  designated 
as  suppurative  and  purulent  mastitis  respectively. 


6  Anatomy,  Pathology  and  Histology  of  the  Mammary  Gland. 

The  acute  forms  of  mastitis  interest  those  engaged  in  milk 
hygiene  but  little,  since  noticeable  changes  in  the  milk  quickly  fol- 
low the  commencement  of  the  inflammation,  and  the  animals  soon 
stop  their  secretion.  On  the  other  hand  the  hidden  forms  of  inflam- 
mation are  of  the  greatest  importance  because  the  milk  is  fre- 
quently almost  unchanged,  and  does  not  always  indicate  its  ined- 
ible condition.  Such  conditions  of  the  udder  may  vary  from  a 
simple  catarrh  to  a  purulent  inflammation.  The  manifestations 
of  these  forms  of  inflammation  vary  to  a  great  extent,  and  the 
symptoms  may  be  only  slightly  pronounced,  so  that  a  single  clin- 

Fig.  2. 


Fibrinous  form  of  parenchymatous  mastitis;  separation  of  quarters  plainly  visible.      (After  Kitt.) 

ical  examination  may  cause  a  suspicion,  but  a  positive  diagnosis 
cannot  always  be  established. 

Literature  shows  that  slightly  marked  swelling  of  the  affected 
quarters,  increased  local  temperature,  nodular  formation  of  the 
parenchyma,  and  induration  of  the  glandular  tissue,  may  appear 
in  the  most  varied  forms,  sometimes  with  and  sometimes  without 
general  symptoms.  At  the  beginning  it  may  be  localized  around 
the  base  of  the  teats,  but  the  hardening  of  the  glands  then  pro- 
gresses forward,  upward  and  backward  (Sven  Wall). 

The  examination  of  the  milk  ducts  should  not  be  neglected. 
The  mucous  membrane  of  the  cistern  may  have  become  inflamed, 


Pathological  Anatomy  of  the  Udder. 


resulting  in  ulcerations,  scar  formations  or  polypoid  prolifera- 
tions, which  are  difficult  to  recognize.  Sometimes  such  changes  of 
the  teats  are  characterized  by  cicatricial  contractions  (strictures). 
The  udder,  which  usually  becomes  affected  in  the  individual  quar- 
ters, may  remain  either  normally  soft,  or  may  become  somewhat 
harder  in  consistence.  The  yellowish-red,  normal  color  of  the 
cross-section  disappears,  and  changes  into  a  grayish-orange  or 
brownish-gray  tinge.  The  parts  which  are  of  a  harder  and  tougher 
consistence  show  an  increase  of  connective  tissue;  the  interstitial 
connective  tissue  changes  into  a  bluish-white  thickened  network. 

Fig.  3. 


Purulent    mastitis    showing    necrotic    foci.      (After    Kitt.) 

The  edema  of  the  skin  which  develops  at  the  beginning  of  the 
inflammation  results  sometimes  in  extensive  sclerosis,  even  the 
parenchyma  of  the  glands  being  sometimes  dislodged  by  the  pro- 
liferating connective  tissue  causing  the  quarter  to  atrophy  and 
harden. 

Tuberculosis  although  almost  invariably  resulting  from  a 
hematogenous  infection,  appears  either  in  the  form  of  a  single 
focus  (tuberculosis  uberis  circumscripta),  or  it  may  be  dissemi- 
nated over  the  entire  parenchyma  (tuberculosis  embolica  dissem- 
inata),  or  the  tissue  may  be  diffusely  affected,  becoming  infiltrated 
throughout  almost  its  entire  extent  (tuberculosis  diffusa).  These 


3  Anatomy,  Pathology  and  Histology  of  the  Mammary  Gland. 


forms  of  the  disease  may  be  present  in  combination  in  the  same 
udder.  During  the  tuberculous  invasion  nodular  indurations  of 
the  tissue  develop,  which  hypertrophy  and  become  tense,  hard  and 
knotty.  The  lymph  glands  usually  manifest  hard,  painless,  thick- 
ening, and  nodular  formations.  Caverns  may  also  develop  in  tu- 
berculosis of  the  udder. 

Actinomycosis  which  commonly  develops  from  the  penetration 
of  actinomycotic  barley  beards,  or  particles  of  straw  into  the 
tissue,  or  more  rarely  by  embolic  infection,  may  also  be  produced 
experimentally  by  the  injection  of  solutions  containing  actin- 
omyces  through  the  milk  ducts.  Actinomycosis  of  the  udder  has 
been  observed  in  cows  by  Peterson,  Rasmussen,  Bang,  Harms,  and 
Jensen.  Nodular  formations,  connective  tissue  proliferations  and 
softening  of  the  tissues,  localized  or  in  larger  areas,  are  also  ob- 
served in  this  disease. 

Botryomycosis  and  glanders  enter  into  consideration  only  so 
far  as  the  udders  of  mares  are  concerned. 

For  completeness,  various  growths  may  also  be  mentioned  as  anomalies  of  the 
udder,  such  as  fibroma,  adenoma,  adenofibroma,  adenocareinoma,  chondrofibroma,  chon- 
droma,  lipoma,  sarcoma,  angioma,  etc.,  which  are  dependent  on  the  tissue  elements  and 
the  character  of  the  tissues  of  which  they  are  composed.  Cystic  formations  have  also 
been  observed. 

Not  infrequently  the  connective  tissue  and  the  subcutis  of  the  udder  of  cows  may 
show  bone  formations  in  the  form  of  bony  hooks  and  plates,  (ossificatio  plana  or 
racemosa).  Parasites  have  also  been  found  in  the  udders  of  cows,  namely  echinococci 
(Behmert  and  Steuding).  For  further  information  see  Kitt,  Pathol.  Anatomy,  1910, 
Vol.  1,  page  280. 

The  author  once  concluded  that  a  goat  affected  with  adenoma  papilliferum  uberis 
was  troubled  with  mastitis,  basing  this  decision  upon  an  examination  of  the  milk,  although 
the  secretion  contained  no  specific  inflammatory  agents.  The  continually  increasing 
quantity  of  milk  was  remarkable.  Postmortem  and  histological  examination  finally 
revealed  the  adenoma  in  the  udder. 

Structure  of  the  Tissue 

The  external  skin  of  the  teats  possesses  neither  hair  nor 
sebaceous  or  sweat  glands,  and  continues  as  cutaneous  mucous 
membrane  into  the  milk  ducts,  which  it  lines  up  to  the  cistern.  The 
mucous  membrane  has  no  glands,  possesses  fine  folds  running 
lengthwise,  and  is  covered  by  pavement  epithelium  which  is 
supported  upon  a  well  developed  papillary  base,  and  is  firm  and 
horny  next  to  the  lumen.  The  papillae  are  extraordinarily  long: 
they  apparently  branch  near  the  base,  and  slant  towards  the 
orifice  of  the  teats.  This  cutaneous  mucous  membrane  of  the 
milk  ducts  continues  without  demarcation,  with  the  mucous  mem- 
brane of  the  milk  cistern,  which  is  covered  by  several  layers  of 
cylindrical  epithelium,  and  possesses  accessory  glands  which  are 
lodged  in  the  connective  tissue.  The  wall  of  the  teats  contains 
bundles  of  involuntary  muscles  running  lengthwise  and  crosswise, 
forming  a  strong  and  elastic  encasement  around  the  canal  of  the 
teats. 

The  supporting  structure  is  penetrated  by  numerous  blood 


Structure  of  the  Tissue. 


9 


vessels  and  lymph  vessels.     Numerous  and  strong  elastic  fibres 
strengthen  the  dense  fibrillar  connective  tissue  of  the  teats. 

In  order  to  describe  the  finer  structure  of  the  parenchyma  of 
the  udder  it  is  necessary  at  first  to  touch  on  the  further  develop- 
ment of  the  organ  from  birth  until  the  moment  of  the  appearance 
of  the  secretion. 

(a)     Normal  Appearance. 

The  milk  gland  is  an  organ  which  performs  increased  func- 
tions only  at  certain  times.  It  does  not  secrete  during  the  entire 

Fig.  4. 


Vertical  section  through  the  lower  end  of  the  teat  canal  which  is  closed  by  a  horny  plug  (a). 

life  but  only  when  the  newly  born  offspring  is  to  be  nourished  by 
the  milk.  The  udder  of  a  virgin  animal  does  not  correspond  even 
in  its  finer  structure,  with  the  appearance  of  a  fully  secreting 
udder,  and  this  again  varies  in  its  finer  structure  from  a  gland 
which  is  at  the  beginning  or  at  the  end  of  the  lactation  period ;  even 
this  is  not  all,  since  the  microscopical  appearance  changes  in  ac- 
cordance with  the  condition  of  activity,  where  a  lobule  or  only  a 
part  of  the  lobule  may  be  found  on  examination,  depending 
whether  the  cell-complex  is  just  forming  the  secretion  or  has  al- 
ready discharged  its  secreted  product. 

The  gland  of  a  newly  born  calf  shows  but  relatively  few  cell  tubes  and  cell  buds, 
imbedded  in  connective  tissue  rich  in  fat  and  branching  in  all  directions.  These  prac- 
tically form  the  basis  of  the  glandular  ducts  and  are  without  alveoli.  The  end  of  the 
tubes  is  frequently  somewhat  dilated,  or  thickened  in  the  form  of  a  club. 


10 


Anatomy,  Pathology  and  Histology  of  the  Mammary  Gland. 


With  puberty  the  alveoli  appear  in  the  cow  surrounded  by  strong  connective  tissue. 
In  older  virgin  individuals  they  sometimes  show  a  slight  amount  of  secretion. 

A  considerable  increase  of  the  glandular  tubes  appears  only 
after  the  first  conception.  The  tubes  become  more  dilated  and 
branch  more  and  more,  forming  alveoli,  from  which  other  ducts 
bud  out. 

Although  indications  of  secretions  in  the  cells  may  not  yet  be 
visible,  the  cavities  contain  a  homogenous  or  fine  granular  mass 
of  cells  or  cell  fragments.  The  gland  prepares  for  the  secretion, 
growing  at  the  expense  of  the  atrophying  or  expanding  connective 
tissue,  until  ready  to  commence  its  secretion. 


Fig.  5 


Superior  portion  of  the  teat  canal   (a)   with  a  reflection  of  the  cutaneous  mucous  membrane 

of  the  cistern  (b). 

The  cell  lining  of  the  larger  glandular  ducts  is  of  double 
layers,  as  in  the  cistern,  while  that  of  the  smaller  ducts  and  al- 
veoli is  composed  of  only  a  single  layer.  The  epithelium  of  the 
latter  appears  cubical  or  flat,  while  the  upper  layer  of  the  former 
is  cylindrical;  in  the  deep  layer  the  cells  are  more  cubical  and 
rounded,  partly  wedged  in  between  the  bases  of  the  superficial 
cylindrical  cells.  The  borders  of  the  cells  are  sharp  and  the  proto- 
plasma  is  clear.  The  nuclei  of  the  epithelia  frequently  show  mi- 
tosis, that  is,  division  and  multiplying  forms.  The  cells  rest  on  the 
so-called  basket  cells  and  the  membrana  propria.  The  basket  cells 


Structure  of  the  Tissue. 


11 


should  be  considered,  according  to  the  investigations  of  Benda  and 
Bertkau,  as  involuntary  muscle  cells  because  of  their  appearance 
and  their  staining  qualities.  They  probably  play  a  part  in  the 
emptying  of  the  glandular  ducts  and  the  milk  secretion. 

Blood  capillaries,  lymph  vessels  and  nerves  run  in  the  inter-and  intra-lobular  con- 
nective tissue,  which  is  strengthened  by  elastic  fibres,  and  contains  involuntary  muscle 
cells.  Therefore,  the  same  tissue  elements  are  represented  as  in  the  teats,  with  the  ex- 
ception of  the  many-layered  pavement  epithelium. 

Fig.  6. 


Structure    of    the    mammary    gland    in    secretion,    Hematoxylin.     1    X  800. 
(a)    Secreting  glandular  alveoli,      (b)  Alveoli  with  dormant  cells. 

At  the  end  of  pregnancy  the  picture  again  changes  consid- 
erably. The  protoplasm  of  the  previously  clear  epithelial  cells  of 
the  secretory  system  becomes  cloudy,  the  nuclei  larger,  their  chro- 
matin  collects  in  flakes  on  the  periphery  of  the  nuclei,  the  borders 
of  the  cell  become  indistinct,  the  cells  become  swollen,  the  nucleus 
lies  in  the  center,  and  the  indications  of  the  division  by  indirect 
fission  of  the  nucleus  appear  relatively  in  groups.  Some  epithe- 
lial cells  show  two  nuclei  at  this  stage;  towards  the  alveoli  fat 
globules  appear.  Leucocytes  with  which  a  few  eosinophiles  are 
mixed,  collect  beneath  the  epithelial  cells  and  penetrating  the 


12 


Anatomy,  Pathology  and  Histology  of  the  Mammary  Gland. 


epithelial  layer,  separate  themselves  from  the  epithelial  cells  and 
enter  the  alveoli,  which  at  this  stage  contain  fatty  secretions, 
leucocytes  and  epithelial  cells  in  all  stages  of  degeneration. 

With  these  manifestations  the  gland  cell  commences  its 
function.  The  desquamation  of  epithelial  cells  and  the  cell  de- 
generation disappear;  the  cellular  infiltration  of  the  connective 
tissue  recedes  until  it  is  very  slight  between  the  now  greatly  di- 

Fig.  7. 


2. 


Chronic  mastitis  of  cow.     1  X  800. 

(a)    Thickened    interstitial    tissue,      (b)    Alveoli,      (c)    Blood   vessels. 

(1)     Epithelial     desquamation.      (2)     Colostra!     bodies.      (3)     Cellular     infiltration. 

(4)    Fatty  degeneration  and  necrosis.      (5)    Milk  concrement. 

lated  and  distended  glandular  ducts.  The  cells  are  finely  granular 
on  the  basilar  border,  and  at  times  show  striation,  that  is,  fine 
streaks  running  in  parallel  directions  (bioplasts  according  to 
Altmann). 

The  nucleus  is  large  and  vesicular  in  shape ;  the  upper  part  of 
the  cell  is  granulated  and  shows  large  and  small  fat  globules.  This 
granulation  and  streaking  may  be  seen,  according  to  Steinhaus 
and  Duklert,  at  each  act  of  secretion.  The  fine  fat  globules  collect 


Structure  of  the  Tissue. 


13 


into  larger  ones,  which  are  only  separated  from  the  lumen  by  fine 
protoplasm,  or  having  been  expelled  have  already  entered  the  al- 
veoli. With  the  collection  of  the  secretion  these  dilate,  the  cell 
becomes  flattened  during  the  expulsion  of  its  products,  and  the  part 
lying  towards  the  lumen  appears  indistinctly  bordered  as  if 
shredded  after  the  expulsion  of  the  fat.  They  soon  become  smooth 
again,  and  by  the  pressure  of  the  alveolar  contents  and  the  dilation 


a 


Chronic  mastitis  of  cow.      1  X  90. 
(a)    Healthy  portion,      (b)    Glandular  portion  with  chronic  mastitis. 

of  the  alveoli,  the  cells  sink  and  become  so  flat  that  the  nuclei  not 
infrequently  appear  bulged  out  towards  the  lumen.  After  the 
expulsion  of  the  secretion  the  formation  of  additional  secretion 
again  commences  in  the  cell,  the  protoplasm  again  becomes  cloudy 
and  granular,  and  so  on,  a  continuous  change  of  the  form  of  the 
cell  taking  place. 

During  the  entire  lactation  period,  but  more  so  in  the  later 
stages,  manifestations  of  atrophy  of  the  gland  appear,  at  first 


14 


Anatomy,  Pathology  and  Histology  of  the  Mammary  Gland. 


commencing  at  the  base  of  the  gland,  and  finally  during  the  end  of 
lactation  in  the  entire  udder.  Epithelial  cells  are  thrown  off,  the 
alveoli  become  fewer,  smaller,  and  irregularly  distended,  the  con- 
nective tissue  increases,  and  cellular  infiltration  starts  under  and 
between  the  epithelial  layers.  The  epithelium  contains  no  fat 
globules,  it  is  sharply  bordered  towards  the  alveoli  and  the  pro- 
toplasm becomes  pale.  Finally  the  last  remains  of  the  secretions 

Fig.  9. 


b. 


a. 


b. 


a. 


Acute  streptococcic  mastitis  of  sheep.     1  X  1000. 

(a-1)    Blood  capillaries.    2.   Thrombosis  by  disseminated   streptococci,      (b)    Glandular 

alveoli,    with   clumps   of   streptococci.      (c)    Migration   of   leucocytes   into 

the  infected  alveoli. 

disappear,  the  plasma  cells  and  leucocytes  taking  care  of  the 
resorption. 

At  the  end  of  this  process  the  gland  is  at  rest,  and  the  cow  is 
dry. 

Of  course  these  processes  are  not  always  so  schematically  uni- 
form as  they  have  been  described.  During  the  entire  lactation 
period,  colostrum-forming,  and  retrogressing  lobules  may  be  ob- 


Structure  of  the  Tissue. 


served;  likewise  certain  parts  of  the  udder  may  remain  in  secre- 
tion during  retrogression  until  storing  of  the  secretion,  leucocytic 
resorption  activity  and  connective  tissue  proliferation  cause  them 
to  cease  their  activity. 

(b)     Pathological  Appearance. 

Any  kind  of  irritation  of  the  gland,  such  as  stasis  of  the  milk, 
especially  in  chronic  catarrhs  and  inflammations,  may  result  in  the 
most  varied  kind  of  pathological  conditions,  either  in  mixed  form 
or  individually.  The  manifestations  vary,  depending  upon 
whether  degeneration  and  destruction  of  the  tissue,  or  reparation 
and  recovery  gain  the  predominance. 

Sometimes  desquamation  of  epithelium,  with  or  without  fatty 
degeneration,  occurs  together  with  cellular  infiltration  of  the  in- 
terstitial connective  tissue  and  capillary  engorgement  as  the  only 
indications  of  inflammation ;  or,  on  the  other  hand,  the  changes  in 
the  interstitial  parts  may  be  very  pronounced,  while  the  changes 
of  the  parenchyma  may  be  less  prominent.  The  inter-  and  intra- 
lobular  connective  tissue  extends  forming  thick  indurations,  from 
which  the  separated  epithelium  is  compressed  to  small  necrotic 
nests.  In  other  stages  of  inflammation  the  cellular  infiltration  of 
the  tissue  predominates.  The  alveoli  and  the  milk  ducts  are 
plugged  up  thickly  with  leucocytes,  and  dilated  with  the  pus.  In 
highly  acute  inflammations  the  rapid  breaking  down  of  cells,  de- 
struction of  epithelium,  serous  and  cellular  infiltration  of  the 
tissues  even  to  their  dissolution,  are  the  principal  manifestations. 
The  ducts  and  the  alveoli  are  inundated  with  serous,  bloody  co- 
agulated masses. 

In  stasis  of  the  milk,  and  in  all  inflammatory  manifestations, 
especially  of  the  acute  form,  the  alveoli  contain  hyalin  and  con- 
crement  arranged  in  layers,  in  addition  to  inflammatory  cells  and 
broken  down  cellular  products. 


CHAPTEB  II. 

PHYSIOLOGY  OF  LACTATION  AND  CHARACTERISTICS  OF 
MILK  IN  GENERAL. 

As  already  mentioned  the  udder  secretes  only  in  certain 
lactation  periods  between  births.  The  lactation  lasts  under  nat- 
ural conditions  in  healthy  animals  as  long  as  the  young  needs 
the  glandular  secretion  for  its  nourishment,  and  stimulates  the 
lactation  by  the  irritation  of  the  intermittent  suckling.  Shortly 
before  parturition,  or  at  the  time  of  parturition,  the  glandular 
tissue  terminates  its  increase  in  development,  and  the  milk  secre- 
tion starts  and  becomes  actively  established. 

The  causes  of  the  increased  cell  production  during  pregnancy, 
and  for  the  secretion  after  this  time,  are  variously  explained. 
Nervous  irritation  from  the  genitals  to  the  milk  glands  may  by 
means  of  reflex  action  stimulate  the  glands  into  activity. 

That  such  reflexes  on  the  genitals  may  originate  from  the 
milk  gland  is  proven  (Pfaundler).  Reflex  actions  in  the  opposite 
way,  however,  have  not  been  proved  (Halbau). 

It  has  been  impossible  either  experimentally  (extirpation  of 
the  lumbar  cord)  or  by  accident  (fracture  of  the  spine),  to  pro- 
duce a  complete  " nervous  isolation,"  since  as  emphasized  by 
Pfaundler,  there  are  still  remaining  the  nervous  connections 
through  the  vasomotors.  However,  the  re-section  of  nerves,  oper- 
ations on  the  spinal  cord,  transplantation  experiments,  etc.,  by 
Eckhardt,  Rohrig,  Sinety,  Busch,  Mirnow,  Piaster,  Ribbert,  Golts 
and  Ewald  would  suggest  that  besides  the  nervous  influences, 
which  undoubtedly  exist,  there  must  be  some  other  agent  which 
stimulates  continuous  growth  during  pregnancy,  terminates  the 
same  with  the  end  of  parturition,  and  inaugurates  the  secretion. 

Hematogenic  influences  may  be  readily  accepted,  as  they  may 
be  led  to  exert  their  action  either  by  the  quantity  or  by  the  quality 
of  the  blood. 

After  parturition  the  body  and  the  milk  gland  have  at  their 
command  great  quantities  of  blood  which  was  previously  utilized 
by  the  gravid  uterus.  The  plethora  which  appears  at  this  time 
may  be  held  responsible  for  the  inauguration  of  the  secretion, 
after  the  udder  has  been  rendered  ready  for  action  by  the  increase 

16 


Milk  Secretion. 


of  its  growth  through  nervous  influences.  On  the  other  hand  it 
has  been  observed  that  in  other  conditions,  in  which  there  exist 
also  a  diversion  of  great  quantities  of  blood  from  the  genital  parts 
for  the  supply  of  other  organs,  as  for  instance  after  operation  on 
very  large  tumors  in  the  region  of  the  genital  organs,  no  secre- 
tion appears  even  when  the  udder  is  prepared  for  the  secretion. 

As  a  matter  of  fact  the  secretion  may  commence  before  birth, 
and  even  in  early  abortions,  or  if  the  fetus  dies.  At  times  when 
the  uterus  is  only  so  slightly  distended  that  the  quantity  of  blood 
set  free  after  abortion  is  hardly  sufficient  for  an  effective  hypere- 
mia  of  the  milk  gland,  the  secretion  of  milk  may  result  (Sinety, 
Kreidl,  Mandl).  Therefore  the  explanation  that  the  quantitative 
influences  of  the  blood  may  give  rise  to  a  stimulation  of  the  milk 
secretion  (Freund),  can  scarcely  be  accepted.  Consequently  the 
qualitative  changes  of  the  blood  must  be  considered  as  more  prob- 
able factors. 

Authors  have  diversified  opinions  upon  this  question. 

While  some  accept  the  view  that  substances  are  eliminated 
from  the  impregnated  organs,  or  by  the  fetus  itself  into  the  blood 
of  the  mother  by  internal  secretions,  and  that  these  act  as  stimu- 
lants on  the  milk  glands,  others  believe  that  the  factors  causing 
lactation  lie  in  the  assimilation  of  certain  nutritive  substances. 

The  supporters  of  the  theories  of  "stimulation  substances" 
(Sinety,  Halban,  Starling)  take  the  stand  that  stimulating  sub- 
stances which  cannot  be  utilized  for  the  cellular  growth  and  cellu- 
lar activity,  contrary  to  the  nutritive  substances,  cause  the  devel- 
opment of  the  gland  during  pregnancy,  and  at  the  same  time  pre- 
vent it  from  secreting  (stimulines,  hormones  [I  stimulate],  sub- 
stances of  pregnancy).  Development  of  the  gland  and  prevention 
of  secretion  may,  of  course,  be  the  action  of  one  and  the  same  sub- 
stance (Hildebrand,  Starling),  or  its  development,  as  long  as  the 
growth  continues,  may  retard  secretion.  With  birth  the  stimula- 
tion of  growth  and  development  ceases,  and  secretion  commences. 

Contrary  to  this,  the  theories  of  nutritive  substances  empha- 
size the  fact  that  the  glands  at  times  may  start  the  specific  activity 
without  the  presence  of  certain  stimulines,  probably  through  nutri- 
tive substances  which  are  present  in  the  blood  at  various  times. 

Eauber  attempts  to  explain  the  activity  of  the  gland  after 
birth  by  declaring  that  after  the  expulsion  of  the  fetus  a  nutritive 
material  becomes  available,  which  has  served  prior  to  birth  for 
the  preparation  of  nutriment  for  the  offspring.  While  the  ex- 
planation of  the  author  that  the  lymph  cells  play  the  most  impor- 
tant part  in  this  can  no  longer  be  considered,  still  it  furnishes 
the  basis  for  all  new  theories  relating  to  the  action  of  nutritive 
substances. 

These  views  were  strengthened  in  1908  by  Schein  by  the  state- 
ment that  during  pregnancy  the  mother  animal,  in  order  to  meet 
the  requirements  of  the  fetus  and  of  the  impregnated  organs,  en- 


18         Physiology  of  Lactation  and  Characteristics  of  Milk  in  General. 

riches  her  blood  with  the  so-called  "milk  producing  substances." 
Pfaundler  recommends  the  designation  "offspring  nutritive  pro- 
ducing substances."  Since  during  pregnancy  the  continuously 
developing  placenta  utilizes  and  consumes  these  substances  for  use 
in  the  nourishment  of  the  young,  there  remain  for  the  milk  gland 
only  slight  remnants,  just  sufficient  to  result  in  the  necessary  stimu- 
lation for  the  cellular  increase  in  the  gland.  After  parturition 
when  the  activity  of  the  placenta  is  completed,  the  milk  gland  takes 
up  the  released  nutritive  substances  for  its  own  use  (specific  af- 
finity of  the  substances  to  the  cells  of  the  milk  gland),  and  is 
stimulated  to  secretion  by  the  quantity  of  the  disposable  material. 
Schein's  milk  producing  substances  in  the  blood  constitute  the 
initial  material  for  the  formation  of  specific  components  of  the 
milk,  milk  sugar,  casein  and  milk  fat. 

The  material  acquired  by  the  mother,  through  placental  con- 
tact with  the  fetus,  while  aiding  in  the  development  of  the  latter 
is  also  of  benefit  to  the  activity  of  the  milk  gland,  whose  product 
adapts  itself  exactly  to  the  requirements  of  the  young,  as  far  as 
it  concerns  the  material  which  the  young  uses  for  the  growth  of 
its  body. 

If  conception  again  takes  place  the  developing  placenta  of 
the  new  fetus  enters  into  competition  with  the  lactating  gland,  and 
draws  from  it  milk  producing  substances  for  its  own  use,  whereby 
the  secretion  of  the  milk  gland  becomes  reduced  or  ended. 

Influences  exerted  on  the  milk  gland  by  oestrum  or  puberty, 
and  also  the  impulse  of  pregnancy,  have  not  yet  been  sufficiently 
explained  through  this  theory.  Pfaundler  enlarges  upon  and  ex- 
plains these  phenomena  by  stating  that  the  withdrawal  of  certain 
nutritive  substances,  through  the  germinal  gland,  embryo  and 
ovum,  and  not  the  appearance  of  milk  producing  substances  alone, 
periodically  disturb  the  equilibrum  of  physiologically  acting  sub- 
stances in  the  blood,  and  thereby  the  antagonizers  of  those  sub- 
stances (the  stimolines,  harmones  of  other  authors),  are  enabled 
to  find  specific  receptors  (affinities)  in  other  organs  of  the  genital 
apparatus. 

After  birth,  continuing  intermittent  stimulation  may  retain  or 
increase  the  lactation  of  the  milk  glands  for  a  longer  or  shorter 
time.  Stasis  of  the  milk  diminishes  and  retards  the  secretion. 

Rievel  opposes  Schein's  view,  since  in  his  opinion  it  does  not 
explain  how  udders  of  animals  in  which  neither  pregnancy  nor 
birth  has  preceded,  could  start  secretion  (lactation  of  milk  glands 
of  the  newly  born  or  virgins,  occasionally  even  of  male  animals). 
According  to  the  author's  view  these  facts  would  not  oppose  the 
theory  of  nutritive  substances.  Schein,  himself,  aims  to  bring 
these  observations  into  harmony  with  his  views,  and  asserts  that 
the  newly  born  may  give  a  secretion  from  their  milk  glands,  when 
towards  the  end  of  pregnancy  the  activity  of  the  placenta  is  dis- 
turbed, and  as  a  result  small  quantities  of  the  "milk  producing 


Milk  Secretion. 


substances"  enter  without  changing  directly  into  the  blood  of  the 
fetus,  and  thence  into  its  milk  gland.  Sufficient  stimulation  for 
the  secretion  and  formation  of  the  so-called  "witches  milk"  re- 
sults. Schein  explains  the  formation  of  milk  in  virgin  mammae,  or 
in  milk  glands  of  individuals  which  have  passed  their  climacteric, 
by  the  fact  that  through  the  stimulation  produced  by  sucking,  the 
secretory  cells  are  awakened  from  their  dormant  state  and  then 
utilize  the  milk  producing  substances  in  the  blood  for  the  perform- 
ance of  their  functions.  Finally  (1910)  he  concludes  that  the  oc- 
currence of  milk  secretions  in  nullipera  and  in  wromen  who  have 
passed  the  climacteric,  which  differs  from  the  gradually  inaugu- 
rated normal  lactation  as  a  result  of  pregnancy,  and  also  the  ob- 
served secretion  by  the  breasts  of  newly  born  and  of  male  indi- 
viduals, represents  a  continuous  secretion  analogous  to  the  normal 
secreting  process  in  other  glands,  in  which  the  product  is  as  a  rule, 
however,  re-absorbed  by  the  glandular  elements.  In  pregnancy  and 
at  birth  the  secretion  is  increased  to  the  greatest  extent,  but  other 
stimulants  may  under  certain  conditions  stimulate  the  activity  of 
the  gland.  Duval's  more  recent  observations  contain  data  relative 
to  the  occurrence  of  milk  secretion  by  women  outside  of  their 
normal  lactation  periods. 

It  is  not  uncommon  to  observe  secretions  in  virgin  animals 
especially  when  young  animals  which  are  present  stimulate  the 
udder  intensively  by  sucking.  It  should  be  emphasized  however 
that  the  udder  secretion  of  virgin  animals  distinguishes  itself  in 
its  appearance  from  the  milk  of  mature  milking  animals ;  it  repre- 
sents a  secretion  which  does  not  even  deserve  the  name  of  milk. 

The  experiments  which  were  conducted  by  various  authors 
in  support  of  their  lactation  theories  appear  of  interest. 

The  experiments  of  Starling  aim  to  show  the  presence  of 
bodies  in  the  blood  during  pregnancy  which  prevent  secretion,  in 
which  claim  is  made  that  an  interruption  of  pregnancy  in  rabbits 
at  a  time  in  which  alveoli  capable  of  secretion  were  not  yet  present, 
led  to  a  retrogression  of  the  milk  gland,  while  in  the  later  periods 
of  pregnancy  secretion  was  induced. 

According  to  Pfaundler's  view  the  harmone  theory  could  be 
effectively  supported  by  the  fact  that  an  existing  secretion  may 
be  successfully  interrupted  or  prevented  by  the  introduction  of 
serum  of  pregnant  animals  of  similar  species. 

The  author  does  not  believe  that  this  proof  is  satisfactory  and 
mentions  observations  made  in  a  case  in  which  the  secretion  ap- 
peared at  birth  of  twins  which  were  born  at  long  intervals,  thaHs, 
the  pregnancy  continued  after  the  first  birth,  yet  the  milk  secretion 
continued  unchecked.  Wucherer  observed  a  case  in  which  a  sow 
gave  birth  to  nine,  and  seventeen  days  later  to  six  other  pigs.  At 
the  birth  of  the  second  lot  the  first  born  pigs  were  taken  from  the 
sow.  These  continued  to  thrive,  but  of  the  second  lot  only  three 
remained  alive.  He  emphasizes  the  opinion  that  a  transitory 


20          Physiology  of  Lactation  and  Characteristics  of  Milk  in  General. 

action  of  blood  serum,  as  used  in  Pfaundler's  experiment,  which 
corresponds  only  slightly  in  its  composition  with  the  normal  blood 
serum,  can  never  be  favorably  compared  with  natural  influences 
in  the  body.  This  exception  must  hold  also  for  the  indecisive  ex- 
periments of  Starling,  who  by  injections  of  juices  from  rabbit  em- 
bryos, but  not  with  injections  of  preparations  from  rabbit  ovaries, 
placentas  and  mucous  membrane  of  the  uterus,  produced  a  devel- 
opment of  the  glands,  and  at  times  a  degree  of  milk  secretion.  He 
believes  that  the  true  cause  of  the  secretion  may  be  found  in  the 
chemical  changes  which  are  produced  by  the  growing  embryo  and 
are  brought  to  the  glands  through  the  placental  circulation.  Ac- 
cording to  Basch,  secretion  may  be  established  in  the  mammary 
glands  of  virgin  rabbits  by  injecting  them  with  placental  extract 
(serum  of  unlike  origin,  from  man),  which  was  so  powerful  that  it 
also  brought  on  a  secretion  of  milk  in  mother  animals  without  the 
intervention  of  pregnancy.  The  placental  extract  could  induce  the 
secretion  only  when  the  teats  of  these  animals  were  stimulated  to 
hyperplasia  by  the  implantation  of  ovaries  from  pregnant  animals. 

According  to  the  author's  observations  these  questions  can 
only  be  determined  through  experimentation,  when  by  uniting  two 
female  individuals  of  like  species  a  basic  condition  is  established, 
by  which  the  activity  of  the  glands  of  one  of  the  impregnated  indi- 
viduals as  a  consequence  of  its  pregnancy  may  be  observed  upon 
the  other,  and  the  result  of  the  impregnation  of  the  latter  on  the 
lactation  of  the  first  mother  may  also  be  determined,  Such  experi- 
ments have  already  been  made  by  Cristea  of  Vienna,  by  coliotomy 
of  a  virgin  and  a  pregnant  animal,  and  uniting  both  by  suturing  of 
the  peritoneum,  the  musculature  and  the  skin,  the  author  establish- 
ing a  double  individual,  united  by  a  broad  peritoneal  communica- 
tion. Of  eighteen  such  pairs  (rats  and  rabbits)  six  remained  alive. 
In  the  experiments  after  parturition  of  the  gravid  animals  the  milk 
secretion  also  appeared  in  the  virgin  animals  to  which  they  were 
united.  Cristea  therefore  believes  in  a  slow  transition  of  a  secretion 
from  the  gravid  animal  into  the  non-impregnated  animal,  namely 
by  the  way  of  the  lymphatics,  since  there  existed  no  blood  vessel 
union  between  the  individual  animals.  With  this  result  the  hypoth- 
esis that  the  changed  distribution  of  the  blood  after  birth  pro- 
duces the  milk  secretion  collapses,  since  on  account  of  the  lack  of 
communication  of  the  blood  vessels  it  is  not  possible  that  an  in- 
creased blood  supply  of  the  mammae  of  the  virgin  animal  would 
result  from  parturition  of  the  attached  animal.  It  can  make  no 
difference  whether  milk  producing  substances  or  substances  which 
are  not  assimilable  and  are  not  consumers  of  energy  (stimulating 
and  inhibiting  substances),  stimulate  the  glands  to  activity. 

Recently  Basch  observed  an  abnormal  birth  to  one  of  a  pair  of 
twins  (the  Blazek  sisters  showing  a  condition  of  pygopagus,  union 
of  the  pelvis  and  sacrum  with  a  common  introitus  vagina?,  and  a 
common  rectum),  in  which  after  the  birth  of  a  child  to  one,  lacta- 


Milk  Secretion.  21 


tion  commenced  also  in  the  virgin  sister.  In  this  instance  nervous 
connections  may  exist  in  the  genitals  of  both  individuals.  Accord- 
ing to  the  author's  view  this  case  is  not  an  absolute  proof  of  the 
stimulation  of  the  gland  by  hematogenic  means. 

The  lactation  theories  may  be  laid  aside,  and  consideration 
only  be  given  to  the  fact  that  at  birth,  puberty,  pregnancy,  at  the 
conclusion  of  parturition  and  also  in  the  disturbances  of  the  gen- 
itals influences  are  exerted  on  the  milk  gland  the  character  and 
action  of  which  are  still  uncertain,  although  the  results  manifested 
by  the  production  of  milk  may  readily  be  observed.  Especially 
typical  and  striking  are  the  phenomena  seen  at  puberty  and  during 
and  at  the  end  of  pregnancy.  Exceptionally  a  condition  may  ap- 
pear outside  of  these  normal  periods  of  the  organs  in  females,  and 
in  single  cases  even  in  male  individuals,  which  permits  the  conclu- 
sion that  the  glands  react  to  special  stimulation.  Abnormalities 
may  occur  in  the  anatomical  structure  of  the  gland,  pathological 
manifestations  in  the  sense  of  inflammatory  reactions,  etc.,  may 
also  be  observed,  and  exceptionally  the  usual  functions  may  be 
present  or  may  develop,  without  their  being  accompanied  by  gross 
anatomical  changes  of  the  gland ;  these  however  are  usually  pres- 
ent at  the  same  time. 

These  influences  on  the  gland  originate  partially  in  the  gravid 
genital  organs  and  the  fetus;  in  other  instances  the  germinal 
glands  and  the  disturbances  of  their  functions  are  the  cause  of 
these  influences. 

Such  influences  may  be  classed  according  to  the  impulses 
which  lead  to  glandular  activity,  as  follows  (Halban) : 

1.  Embryonic    impulse — action    very      transitory — mastitis 
neonatorum — witches  milk. 

2.  Puberty — lasting  effect — development  of  the  gland. 

3.  Oestrum — action    rapidly    transitory — hyperemia,  inter- 
stitial hemorrhages,  disturbances  to  physiological  lactation,  secre- 
tion. 

4.  Impulse  of  pregnancy — lasting  between  parturitions. 
Lactation  may  be  sustained  for  a  long  period  of  time  by  the 

regular  drawing  of  the  milk,  and  ceases  in  healthy  udders  only 
when  after  frequent  and  absolute  stasis  of  the  milk  (after  about 
eight  days),  the  tissue  becomes  affected  by  inflammatory  irrita- 
tions (absorbtion  and  change  of  the  condition  of  the  epithelium), 
or  when  the  animals  are  soon  to  give  birth  to  young.  If  no  re-im- 
pregnation takes  place  the  lactation  period  may  last  longer,  even 
from  one  to  two  years  although  not  to  an  unlimited  extent.  The 
activity  of  the  gland  may  be  retained  for  a  long  time  through  the 
sucking  of  the  young,  stimulation  by  milking,  or  artifical  with- 
drawal of  milk. 

Frequent  periodical  and  complete  emptying  of  the  milk  cis- 
terns acts  favorably  on  the  amount  produced.  In  the  cow  two  to 
three  milkings  per  day  are  sufficient  to  retain  the  udder  in  secretion. 


22         Physiology  of  Lactation  and  Characteristics  of  Milk  in  General. 


The  milk  formation  occurs  between  the  milking  periods  and 
during  the  milkiiigs ;  therefore  of  these  two  periods,  the  first  lasts 
for  many  hours,  the  second  with  more  intensive  production  is  com- 
pleted in  a  few  minutes.  The  first  phase  is  the  work  of  continued 
activity  of  the  gland,  the  second  is  brought  on  under  the  stimula- 
tion of  the  sucking,  or  milking,  on  the  secretory  nerves,  and  as  a 
result  of  the  increased  blood  supply  (stimulation  of  the  vasodila- 
tors). The  capacity  of  all  the  milk  ducts  of  the  udder  represents 
less  than  half  of  the  quantity  of  milk  obtained  in  one  milking. 

According  to  Fleischmann  the  volume  of  the  entire  udder  of  a 
cow  with  the  teats  is  6700  c.  c.  Of  this  3000  c.  c.  is  represented 
by  the  cavities ;  the  secretion  obtained  in  one  milking  may  never- 
theless amount  to  7000  c.  c. 

Niiesch  substantiates  Fleischmann 's  statements  by  an  experi- 
ment; a  cow  gave  daily  before  slaughter  10  liters  of  milk  of 
which  5 . 5  liters  was  the  amount  of  the  morning  milking. 

After  slaughter  before  milking  in  the  morning  2.7  liters  of 
milk  could  be  proven  in  the  udder  (catheterization  and  calculation 
of  the  amount  remaining  in  the  udder),  which  proves  secretion 
during  the  process  of  milking. 

The  two  phases  may  be  considered  as  though  the  glandular 
cells  which  tire  after  the  milking  gradually  recover  (increased 
blood  supply)  and  recommence  their  secretions.  The  collecting 
secretion  will  increase  until  a  certain  relative  pressure  between 
the  collective  quantity  of  secretion  and  the  tissue  with  the  blood 
vessels  is  established,  when  the  secretion  is  retarded  or  ceases  until 
renewed  stimulation  of  the  glands  by  milking,  emptying,  massage, 
(electric  irritation),  or  stimulation  of  the  central  nervous  system 
from  milk  accumulations  causes  the  milk  to  fill  the  cavities  of  the 
udder  again. 

If  the  usual  milking  time  is  omitted  a  flow  of  milk  may  result, 
that  is  the  pressure  under  which  the  secretion  is  held  finally  over- 
powers the  resistance  of  the  sphincter  muscles  at  the  opening  of 
the  teats  (directly  or  by  reflex),  whereupon  formation  of  milk 
again  takes  place. 

Nervous  influences  on  the  secretion  are  exerted  by  the  sper- 
maticus  externus  and  by  the  sympathicus. 

Experiments  which  were  conducted  for  the  study  of  the  ener- 
vating influences  on  the  secretion  produced  contradictory  results. 

Rohrig  severed  the  ramus  inferior  of  the  nervns  spermaticus 
externus  (vessel  branch),  and  observed  an  acceleration  of  the 
secretion,  while  the  severing  of  the  glandular  branch  (part  of  the 
median  branch)  resulted  in  inhibition.  Eckhard  failed  to  observe 
any  influence  on  the  quantity  of  milk  after  the  severing  of  the  ner- 
vus  spermaticus  extermis.  Heidenheim  and  Partsch  demonstrated 
an  increase  of  the  quantity  of  milk  from  the  cutting  of  the  nervus 
spermaticus  externus,  but  only  when  strychnine  or  curare  had  been 
administered  at  the  same  time  (test  by  Sinety  on  guinea  pigs). 


Milk  Secretion.  23 


Although  Basch  could  not  establish  a  quantitative  increase  by  sev- 
ering the  nervus  spermaticus  oxternus,  he  found  qualitative 
changes  (formation  of  colostrum). 

Pfaundler  concludes  from  these  and  other  experiments  that 
an  action  of  the  peripheral  nerves  on  the  development  of  the  gland 
and  its  functions,  especially  from  a  qualitative  point  of  view,  must 
figure  in  the  consideration,  but  that  these  influences  have  only  slight 
importance. 

Insignificant  as  well  in  their  results  on  the  secretion  were  the 
severing  and  re-sectioning  of  the  spinal  cord,  or  interference  with 
the  sympathetic  system.  Basch  again  observed  the  formation  of 
colostral  milk  after  re-sectioning  of  the  coeliac  ganglion.  From 
this  he  concludes  that  the  regulating  influence  of  the  nervous 
system  exists  through  reflex  action,  especially  from  the  sympa- 
thetic, but  that  at  the  same  time  the  gland  is  also  capable  of 
independent  secretion. 

As  a  matter  of  fact  far  reaching  influences  of  a  nervous 
character  are  observed. 

1.  Psychic  influences. 

2.  Eeflexes,  which  are  caused  by  local  stimulations    (sucking 
— milking — electrical  stimulations,  etc.). 

3.  Reflexes  from  the  genital  region. 

These  points  are  only  briefly  mentioned  here,  since  the  various 
conditions  will  be  discussed  in  subsequent  chapters,  when  consider- 
ation will  be  given  to  the  quantitative  and  qualitative  changes 
which  appear  under  varying  influences. 

An  active  part  in  the  emptying  of  the  milk  from  the  cisterns, 
and  in  the  passage  from  the  upper  part  of  the  duct  and  alveolar  sys- 
tems, is  played  by  the  sucking  and  pressure  exerted  during  the. 
milking  (pressing  outwards,  sucking  from  the  gland),  massage  of 
the  udder  (pressing  out  into  the  cistern),  the  contractility  of  the 
tissue  (elastic  fibres,  involuntary  musculature,  filling  of  the  blood 
vessels),  and  the  vis  a  tergo  of  the  newly  formed  secretion. 


CHAPTER  III. 

MICROSCOPY  OF  MILK  IN  GENERAL. 

If  milk  is  examined  through  a  microscope  one  chiefly  sees 
numerous  small  fat  cells  floating  in  the  fluid  or  milk  plasma.  These 
will  be  considered  later,  but  at  first  the  cells  and  cell  fragments 
originating  from  healthy  and  affected  udders  will  be  discussed. 
Between  the  milk  globules,  by  which  term  the  small  fat  droplets 
are  designated,  bodies  may  be  seen  which  are  hard  to  define  unless 
stained.  After  special  treatment,  however,  they  may  be  readily 
recognized  as  cells  or  their  fragments,  or  as  a  precipitation  of 
soluble  or  suspended  substances. 

Since  the  external  skin  of  the  udder,  and  the  lining  of  the  milk 
passages  and  milk  secretory  ducts  in  the  udder  are  of  similar  for- 
mation, we  naturally  are  only  concerned  with  the  upper  layers  of 
pavement  epithelium,  cylindrical  epithelium,  and  the  deeper  cubical 
epithelium  of  the  terminal  ducts  and  alveoli,  and  only  in  severe 
tissue  changes  would  cells  of  other  parenchymatous  parts  appear 
in  the  milk.  Naturally  in  such  an  actively  working  organ,  even  in 
a  physiological  normal  condition,  leucocytes  of  the  most  varied 
kind,  and  even  red  blood  corpuscles  may  be  found.  In  cases  of 
special  stimulation  from  physiological  or  pathological  causes,  the 
resulting  cell  mixture  may  be  of  a  most  varied  character  depending 
upon  the  location  of  the  stimulation,  and  its  quality  and  duration; 
hence  at  times  certain  leucocytes,  and  again  red  blood  cells  or 
epithelia,  may  predominate  in  the  mixture. 

1.  Cells  from  compound  pavement  epithelium.  Following 
the  intensive  manipulation  and  stimulation  of  the  teats  by  milking, 
the  appearance  of  cells  from  the  upper  layers  of  the  pavement 
epithelium  of  the  outer  skin,  and  the  milk  ducts  is  natural.  As 
a  matter  of  fact  in  the  fresh  milking  periods  during  which  irrita- 
tion from  the  extraction  of  the  milk  is  especially  evident,  the 
milk  always  contains  fine  folded  platelets  of  round,  oval,  or  irreg- 
ularly distended  and  curved  borders,  which  frequently  when  folded 
in  several  layers,  appear  as  small  clasped  cysts  without  special 
structure. 

These  bodies  have  been  described  by  Winkler,  and  were  con- 
sidered by  him  as  indications  of  pathological  changes.  The  author 

24 


Cellular  Content  of  Milk. 


25 


took  a  stand  against  this  view  of  Winkler,  as  he  had  observed  them 
in  the  milk  of  entirely  healthy  animals,  but  not  until  the  present 
time  has  he  been  able  to  offer  an  explanation  of  the  nature  of  these 
bodies,  designated  as  "skinlets"  or  " shell."  They  represent 
desquamated  cells  of  the  stratum  mortificatum  of  the  pavement 
epithelial  layers  singly  or  in  groups.  Although  usually  no  parti- 
cular structure  is  manifested  yet  in  single  instances  typical  flat, 
round  nuclei  can  be  seen. 

If  the  teats  of  a  slaughtered  cow  are  taken  and  the  cistern  and 
milk  duct  are  carefully  cut  open,  and  from  the  surface  of  the  milk 
duct  a  small  quantity  of  the 

cellular  layer  is   scraped  Fig.  10. 

off,  an  examination  by  the 
usual  method  discloses  the 
typical  "shells." 

2.  If  cells  from  the 
cistern  are  prepared  and 
examined,     elongated     or 
oval,  or  quadrangular  cells 
with  oval  nuclei,  frequent- 
ly elongated  at  the  base, 
will  be  found,  singly  or  in 
groups.     Single  fat  drop- 
1  e  t  s  may  frequently  be 
seen   in  the  plasma   sur- 
rounding these  cells.  Sim- 
ilar cells  may  also  be  found 
in  normal  milk.    They  are 
usually    single,    although 
sometimes    united    in 
groups  arranged  like  flow- 
ers.   In  stimulation,  which 
brings  on  a  desquamation 
from    the    mucous    mem- 
brane of  the  cisterns,  or 
from  the  parenchyma  in 
catarrhal  conditions  of  the 
milk    passages,    they    of 
course  appear  in  masses. 

Such  reactions  occur  in  the  cistern  for  instance  as  a  result  of 
the  so-called  kneading. 

3.  Cells  from  the  secreting  milk  ducts  and  the  alveoli,  ap- 
pearing large  or  small  according  to  the  quantity  of  fat  globules 
collected  in  them,  often  become  tremendously  distended  and  bloated 
(foam  cells).    Their  structure  is  mostly  honeycombed  or  mulber- 
ry-shaped when  they  contain  fat ;  without  fat  the  cell  is  surrounded 
with  only  a  narrow^border  of  protoplasm.    The  nucleus  is  usually 
in  good  condition. 


Film  of  sediment  from  milk  of  a  fresh  milking  cow. 

Cells  from  the  stratified  layer  of  pavement  epithelia 

of  the  teat  canal.     Thionin.      1  X  1000. 


26 


Microscopy  of  Milk  in  General. 


These  cells  are  the  large  colostral  bodies.  They  are  in  their 
entire  structure  and  in  their  staining  characteristic  epithelial  cells 
and  not  leucocytes ;  the  amoeboid  movements  observed  in  them,  if 
these  observations  were  beyond  questioning,  do  not  prove  that  all 
colostral  bodies  represent  leucocytes. 

This  point  will  be  again  taken  up  during  the  discussion  of  colos- 
trum. While  such  cells  only  appear  occasionally  in  ripe  milk  they 
are  extremely  numerous  at  the  beginning  and  termination  of  secre- 
tion, and  in  pathological  processes,  in  the  latter  especially  in  sub- 
acute  and  chronic  forms,  but  not  in  peracute  and  acute  inflammatory 

conditions  of  the  paren- 
chyma. Such  cells  may 
occasionally  be  noted 
collected  in  groups. 

The  author  believes 
that  their  appearance  in 
masses  in  the  milk,  that 
is,  the  condition  increas- 
ing the  expulsion  of 
these  epithelia,  results 
from  the  fact  that  each 
cell,  which  in  its  singu- 
lar activity  precedes  or 
follows  the  other  cells 
of  the  union,  becomes 
desquamated.  It  does 
not  correspond  func- 
tionally, with  the  other 
cells,  and  is  therefore 
removed  from  the  rows 
of  cells  which  are  de- 
veloping for  a  definite 
purpose  or  are  working 
for  that  purpose.  Only 
when  uniform  work  is 
performed  by  all  of  the 
cells  working  in  unison, 
.„  and  bringing  about  a 

uniform  condition,  will  the  organ  cease  to  free  itself  of  incapable 
elements.  In  inflammation  the  inflammatory  irritation  and  its 
consequences  soon  drive  the  cells  to  overproduction.  At  other 
times  it  paralyses  or  destroys  them,  even  before  the  formation 
m?'  5epending  on  the  d.uration  of  the  inflammation. 
Ihe  form  of  the  epithelium  varies  in  accordance  with  the  con- 
tent ot  fat  The  collection  of  fat  is  not  the  result  of  fatty  degenera- 
tion, but  is  produced  when  the  cell  is  thrown  off  before  its  time  for 
secretion,  or  while  still  capable  of  taking  up  material  and  produc- 
ing tat  but  without  strength  for  the  separation  of  fat.  Therefore 


Cells  from  the  lining  membrane  of  the  wall  of  the  cistern 
Sediment  in  catarrh  of  the  cistern.  Thionin.  1  X  1000.  ' 


Cellular  Content  of  Milk. 


27 


such  cells  may  be  found  even  in  the  epithelial  groups,  which  is  an 
additional  proof  that  they  with  certainty  represent  epithelial  cells. 

The  cells  are  from  5  to  25,  even  to  47  p>  in  size  (Schulz).  Not 
infrequently  2  to  3  nuclei  of  oval  or  roundish  shape  are  present. 
The  author  has  never  observed  more  than  one  nucleus,  and  be- 
lieves, with  Popper  and  Schulz,  that  the  appearance  of  more  than 
one  nucleus  results  from  two  cells  lying  on  each  other,  in  which 
case  the  cell  thus  formed  may  appear  to  possess  two  or  more  nuclei. 
Migrated  macrophages  may  also  simulate  a  polynuclear 
appearance. 

Notinfrequentlyepi-  Fig  12< 

thelial  cells  are  thrown    '      

off,  with  a  single  large 
fat  globule  in  the  body 
of  the  cell,  known  as 
"  seal-ring  cells."  In 
such  cases  the  fat  glob- 
ules have  a  "moon"  or 
"cap"  appearance. 

4.  Leucocytes  of  all 
forms  are  frequently  met 
with  in   milk   such   as 
mononuclear  basophiles, 
eosinophiles,  polynuclear 
basophiles,     acidophiles, 
or  cells  with  neutrophilic 
and  eosinophilic  granules 
in  the  protoplasm. 

If  the  polynuclear 
cells  show  no  nuclear 
bridges,  they  may  be 
found  with  %  or  more 
spherical  shaped  nuclear 
granules  (spherical  gran- 
ule polynuclear  leuco- 
cytes, Babs.)  The  nu- 
cleus is  usually  in  the 
shape  of  a  ribbon,  or  clover  leaf,  or  heartshaped.  The  protoplasm 
usually  contains  fat  globules,  which  in  stained  preparations  appear 
as  fine  vacuoles. 

The  lymphocytes  are  small  cells  with  round  nuclei  and  a  very 
small  border  of  protoplasm.  According  to  Schulz  they  never  con- 
tain fat.  Large  mononuclear  leucocytes  are  also  supposed  to  be 
present  in  the  milk.  If  they  gorge  themselves  with  fat  they  are 
filled  to  their  fullest  extent,  and  can  no  longer  be  distinguished 
from  fat-containing  epithelial  cells. 

5.  The  red  blood  cells  may  be  seen  as  small,  round  or  thorn- 


Sediment  in  milk  of  a  cow  after  milk  stasis.  Numer- 
ous desquamated  epithelia,  among  these  an  "albu- 
minophore,"  and  polynuclear  leucocytes. 


28 


Microscopy  of  Milk  in  General. 


apple  shaped  bodies,  with  metachromatic  staining  substances. 
They  may  be  readily  recognized  as  erythrocytes. 

6.  Degeneration  of  these  various  kinds  of  cells  may  result  in 
the  finding  of  the  most  peculiar  formations. 

The  protoplasm  of  the  epithelial  cells  becomes  shredded ;  the 
nucleus  splits  up  and  eliminates  its  chromatin  into  the  plasma  in 
the  form  of  dust  or  flakes.  It  diffusely  passes  into  the  cell  pro- 
toplasm, which  appears  darkly  stained,  and  in  the  place  of  the 

Fig.  13. 


The   formation   of  large   colostral   spheres   and   desquamation   of    "seal-ring   cells." 

1  X  800. 


nucleus  a  pale  vacuole  appears.  If  the  breaking  down  continues 
there  may  appear  a  disintegration  of  the  cell  and  of  its  nucleus  into 
small  droplets  and  fragments  of  roundish  appearance,  either  with 
or  without  a  lightly  stained  border  around  a  small  darkly  stained 
center  of  chromatin  (Heidenheim,  Cohn,  Popper,  Schulz).  These 
chromatin  flakes  are  probably  identical  with  the  so-called  free 
nuclei  (Michaelis),  which  were  also  observed  by  Lenfers. 

The  flakes  which  result  from  chromatolysis  have  been  des- 


Cellular  Content  of  Milk. 


29 


ignated  up  to  the  present  as  "Nissen's  Globules."  According  to 
Ottolenghi  they  are  derived  either  from  leucocytes  or  from 
epithelia. 

If  fat-containing  cells  break  down  in  this  manner,  fat  globules 
in  the  shape  of  grape-like  bunches,  and  single  fat  globules  result, 
which  are  united  by  a  mesh  of  fine  protoplasm,  or  they  are  sur- 
rounded in  the  form  of  a  moon  by  a  narrow  border  of  protoplasm, 
which  crowded  to  one  side  rests  like  a  cap  on  the  fat  globules. 
Such  moon  and  cap  formations  may  also  result  in  another  way. 
The  leucocytes  (mac- 
rocytes),  crowd  on  to 
the  dead  or  dying  cells, 
eat  their  way  into  the 
cell  bodies  and  establish 
in  the  more  and  more 
distending  cell  actual 


Fig.  14. 


*  * 


*n 


* 


*• 


*  >'; 


•** 

* 

V      . 


C.' 


lacunae,  in  which  the  de- 
vouring leucocytes  lie. 
The  remains  of  the  pro- 
toplasm and  of  the  cell 
and  nuclear  membranes 
float  in  the  shape  of 
caps  and  moons  in  the 
milk  protoplasm  until 
the  swelling  or  further 
breaking  down  converts 
them  into  spheres  or 
globules.  At  the  same 
time  of  course  the  mac- 
rocytes  may  them- 
selves  degenerate  in  the 
cell,  and  no  longer  pre- 
sent a  recognizable  nu- 
cleus. In  such  cases  its 
respective  lacuna  con- 
tains homogeneous, 
sharply  circumscribed 
proteid  globules. 

The  author  considers  these  epithelial  cells  which  have  been  destroyed  by  macro- 
phages,  as  identical  with  the  albuminophores  of  Bab  and  Schulz  which  they  described 
as  large  lymphocytes,  (15  to  20/u.),  containing  fat  and  1  to  4  or  more  proteid  globules. 

Besides  these  regularly  formed  constituents  of  the  milk,  its 
sediment  contains  flaky  constituents,  small  irregular  shaped  coag- 
ula,  which  readily  tinge  with  basic  anilin  dyes,  or  with  nuclear 
staining  substances.  Frequently  they  are  without  any  structure. 
At  times  they  appear  in  individual  milkings,  almost  completely 
dominating  the  microscopical  field.  They  are  the  early  stages  of 
the  corpora  amylacea,  soon  to  be  described,  which  appear  either 


* 





'«• 


Budding  globules,  free  nuclei,  Nissen's  globules,  that  is 

cell  fragments,  in  the  sediment  of  cow's  milk. 

1  X  1000. 


30 


Microscopy  of  Milk  in  General. 


round,  oval,  bean-shaped,  or  nodular,  ranging  from  very  small 
(1  to  2  /A),  to  an  enormous  size  (5  to  200  ^  according  to  Zimmer- 
mann).  These  bodies  show  no  concentric  formation,  or  radial 
stripes.  They  usually  appear  during  abnormal  activity  of  the 
gland,  and  are  found  in  colostrum,  in  stasis  of  the  milk,  in  mastitis, 
in  the  inactive  glands  of  older  animals,  etc.  Their  varied  thickness 
makes  active  turning  of  the  micrometer  screw  necessary. 

These  corpora  amylacea  (according  to  Siegert,  corp.  flava  in  contra-distinction 
from  corp.  versicolorata,  are  the  same  as  amylacea)  were  seen  by  Herz,  Ottolenghi, 
Iwanoff,  and  later  described  by  Martin,  Lenfers,  Winkler  and  Zimmermann.  Wederhake 


Epithelia    in    different    stages    of    destruction    by    macrocytes,    that    is    so-called 
albuminophores.      1  X  1000. 

confirmed  their  occurrence  in  the  colostrum  of  women,  and  compared  them  with  the  corp. 
amylacea  of  the  prostate  gland. 

A  section  offers  the  best  opportunity  for  the  microscopical 
study  of  the  nature  of  these  bodies.  In  preparations  of  acute 
mastitis,  their  development  is  especially  clear.  Around  small 
flakes  of  proteids,  possibly  precipitated  nuclear  or  cell  fragments, 
layer  after  layer  will  be  formed  until  a  concrement  results,  which 
may  even  fill  the  entire  alveolus.  Lime  and  salts  of  magnesium  are 
later  absorbed  by  this  basic  structure  of  concentric  layers,  and  fine 


Milk  Concrements. 


31 


radiated  stripes  appear  upon  its  surface  in  consequence  (Fig.  13, 
Fig.  16  and  Table  L). 

While  the  alveolar  epithelium  succumbs  to  the  pressure  of  the  growing  concrement, 
and  may  be  absorbed  for  some  time,  the  concrement  resists  the  influences  of  the  organs, 
and  finally  is  surrounded  by  connective  tissue.  Zimmermann  states  that  the  bodies  may 
be  either  in  the  alveolus  or  on  or  under  the  epithelial  layer,  and  even  free  in  the  con- 
nective tissue.  These  observations  have  been  confirmed  by  the  author. 

They  stain  with  methylene  blue,  iodine  green,  and  gentian 
violet,  similar  to  other  amyloid  substances,  but  do  not  give  the 
starch  reaction  with 

iodine  solution  and  sul-  Fig.  16. 

phuric  acid  (Zimmer- 
mann, and  author's  ob- 
servations). Wederhake 
and  Winkler  claim  to 
have  obtained  a  bluish 
violet  coloration  with 
iodine. 

The  corpora  amy- 
lacea  of  the  mammary 
glands  resist  few  acids 
(sulphuric  acid,  hydro- 
chloric acid).  Otto- 
lenghi  and  Zimmermann 
obtained  a  solution  with 
pure  sulphuric  acid. 

They  are  therefore 
pure  concrements  of  se- 
cretion which  form  un- 
der peculiar  conditions. 
Their  quality  varies, 
depending  on  the  char- 
acter of  the  precipita- 
tions, which  combine  to 

lOrm   them.  Lime  concrement  in  the  milk  sediment  of  a  cow. 

1  X  1000. 

What  remarkable  significance  may  be  attached  to  such  conditions  may  be  indicated 
by  the  views  of  Herz,  who  considers  them  as  the  initial  formation  of  casein,  and  those 
by  Winkler,  who  believes  that  they  change  into  fat  or  that  they  are  degenerated 
epithelium. 

Leucocytes  also  crowd  upon  these  bodies,  and  attempt  to  dis- 
solve them  just  as  osteoclasts  attack  bones.  Under  their  influence, 
combined  with  that  of  the  body  juices,  a  destruction,  solution  and 
absorption  of  the  concrements  may  take  place,  or  on  the  other  hand 
new  layers  of  thickened  secretion  may  form  around  the  old  debris, 
and  a  new  concrement  develops. 

This  describes,  with  the  exception  of  the  fat  globules,  the  cell 
elements  which  may  be  demonstrated  under  the  microscope,  as  far 
as  they  originate  from  the  udder  of  the  cow.  The  fat  globules  will 
be  discussed  under  the  heading  of  milk  fat. 


CHAPTEE  IV. 

COMPOSITION  OF  MILK  AND  ITS  BIOLOGICAL,  CHEMICAL 
AND  PHYSICAL  CHARACTERISTICS. 

There  is  very  little  known  with,  absolute  certainty  relative  to 
the  development  of  the  individual  constituents  of  milk.  The 
theories  in  this  regard  are  almost  entirely  hypothetical.  It  is 
certain  that  milk  constitutes  the  specific  product  of  cell  activity  of 
the  glandular  parenchyma,  and  does  not  represent  a  simple  trans- 
udation  of  the  constituents  of  blood,  with  a  mixture  of  broken  down 
products  of  cells  (nuclear  masses  of  leucocytes  and  epithelia,  and 
fatty  detritus),  nor  the  fatty  breaking  down  of  the  epithelium 
(Reinhardt,  Virchow,  Skanzoni,  Koelliker),  nor  partial  epithelial 
degeneration  of  the  parts  lying  adjacent  to  the  lurnen  (Heiden- 
hain),  nor  transformation  of  leucocytes  and  lymph  cells  (Rauber). 
None  of  these  is  the  basic  pheonomenon  in  the  formation  of  milk, 
but  it  is  due  instead  to  the  assimilating  activity  of  the  cells,  which 
send  their  secretion  into  the  lumen  of  the  cell  tube  (Ottolenghi). 
A  breaking  down  of  cells  of  course  occurs  to  a  greater  or  lesser 
extent,  in  accordance  with  their  increased  activity,  and  therefore 
the  milk  contains  cells  and  cell  fragments  in  varied  quantities, 
without  this  throwing  off  of  cells  or  breaking  down  of  cells  having 
anything  to  do  directly  with  the  secretion  proper.  The  throwing 
off  of  useless  material,  and  its  natural  replacement  by  functionat- 
ing elements  are  only  signs  that  the  organ  desires  to  maintain  itself 
in  a  condition  capable  of  continued  secretion. 

Our  attention  has  previously  been  directed  principally  to  the 
functions  and  activities  of  the  milk  gland  from  a  physiological  point 
of  view;  the  morphological  condition  of  the  udder  and  some  con- 
stituents of  the  secretion  have  also  been  noted.  In  this  chapter  the 
chemical  qualities  of  the  milk  will  be  considered,  as  far  as  this  is 
necessary  for  the  most  ordinary  conception  of  these  properties. 

The  quality  of  the  milk — in  the  broadest  sense — adjusts  itself 
to  the  requirements  of  the  young.  The  milk  gland  offers  it  nutri- 
tive and  protective  material  in  a  form  which  most  favorably  meets 
the  requirements  of  the  off-spring. 

In  order  to  give  only  a  few  examples  attention  should  be  directed  to  the  estab- 
lished facts,  which  show  that  there  exist  absolute  relations  between  the  time  required 

32 


Composition  of  Milk.  33 


for  the  doubling  of  the  weight  of  the  young  and  the  percentage  of  proteids  in  the  milk; 
between  the  proportion  of  certain  salts  and  the  ash  constituent,  and  the  rapid  growth  of 
the  young ;  between  the  growth  of  the  brain  and  the  supply  of  proteids  and  lecithin. 

Milk  consists  of  dissolved  constituents,  and  this  solution  con- 
tains substances  in  suspension ;  in  the  entire  mixture  there  are  also 
undissolved  substances  in  emulsion. 

The  dissolved  and  suspended  substances  are  designated  as 
milk  plasma,  which  after  coagulation  separates  in  milk  serum  and 
coagulum.  The  fat  is  present  in  an  emulsion;  there  are  in  addi- 
tion to  this  several  salts,  coagulums,  cells,  etc.,  undissolved  or  in 
a  precipitated  condition.  In  coagulation  the  casein  which  at  first  is 
in  suspension,  thickens,  and  carries  down  the  undissolved  sub- 
stances, separating  more  or  less  from  the  milk  serum  in  which  the 
soluble  salts,  milk  sugar,  certain  proteids,  ferments,  coloring  mat- 
ter, etc.,  remain. 

The  principal  constituents  of  the  milk,  which  constitute  as  well 
the  principal  properties  of  the  glandular  secretions,  are  the  parts 
which  have  received  the  most  thorough  study. 

The  proteids.  Casein,  milk  albumen,  and  milk  globulin  (traces 
of  lactomucins,  and  possibly  traces  of  other  proteid  substances, 
which  remain  after  acid  precipitation  and  boiling,  being  known 
collectively  as  lactoproteins)  are  the  protein  constituents  of  milk. 

The  fat;  the  milk  sugar.  The  milk  further  contains  lecithin, 
sarcin,  kreatinin,  nuclein,  urea  and  sulphocyanic  acid. 

Nothing  is  known  at  the  present  time  of  some  of  these  constit- 
uents, whether  they  occur  originally  in  the  milk,  or  whether  they 
are  only  split  products,  which  result  during  the  final  production  of 
the  various  principal  constituents,  or  through  bacterial  action  in 
the  milk ;  of  such  substances  may  be  mentioned  peptone,  ammonia, 
leucin,  etc. 

Of  non-nitrogenous  substances  milk  also  contains  citric  acid, 
cholesterin  and  under  certain  conditions  free  lactic  acid,  alcohol 
and  acetic  acid. 

Gases  which  occur  free  in  milk  are  oxygen,  nitrogen,  and  oc- 
casionally carbonic  acid ;  the  salts  are  combinations  of  the  bases  of 
sodium,  potassium,  magnesium,  calcium,  and  iron,  with  hydro- 
chloric acid,  sulphuric  acid,  phosphoric  acid,  carbonic  acid,  and 
citric  acid. 

Principal  Constituents. 

Casein  is  a  proteid  especially  characteristic  of  milk,  occur- 
ring almost  exclusively  in  the  milk  gland  secretion  of  mammalia,  in 
quantities  of  from  2  to  4  per  cent. 

(It  is  supposed  to  occur  also  in  the  secretion  of  the  sebaceous 
glands  of  mammalia  and  in  the  coccygeal  gland  of  birds.) 

The  origin  of  casein  is  unknown.    It  was  formerly  supposed  that  it  originated  from 

an  enzymic   change   of  serum   albumen  produced  by  the  action  of  enzyme-like  bodies 

upon  the  albumen.     However,  since  it  has  been  found  that  the  assertion  of  Kemmerich, 

relative  to  the  increase  of  the  casein  at  the  expense  of  the  lactalbumen,  after  the  di- 

3 


34  Biological,  Chemical  and  Physical  Characteristics  of  Milk. 

gestion  of  milk  at  blood  temperature  for  several  hours  was  incorrect  (Schmidt  and  Tier- 
felder,  likewise  that  casein  is  not  produced  by  mixing  blood  serum  and  macerated  milk 
gland  structure,  or  milk  gland  juice  and  ovalbumin,  and  especially  since  it  is  known  that 
casein  represents  a  nuclear  albumin  containing  phosphorus,  the  enzymic  origin  of  the 
casein  in  the  above  sense  is  denied.  For  a  time  Basch  's  hypothesis  relative  to  the  origin 
of  the  casein  was  accepted,  namely  that  the  nucleic  acid  which  is  set  free  in  the  alveoli 
by  the  activity  of  the  gland,  combines  with  the  transuded  blood  serum,  forming  the 
nucleo-albumin,  the  "casein."  Investigation  of  the  experiments  of  Basch  by  Odenius, 
Mendel,  Levene  and  Lobisch  proved  however  that  Basch 's  hypothesis  cannot  stand. 

At  the  present  time  it  must  be  admitted  that  the  cells  of  the 
milk  gland  break  up  the  proteids  into  more  simple  bodies,  and  then 
build  up  the  casein  from  these  products. 

The  casein  is  distinguished  from  other  proteids  containing  phosphorus,  as  for  in- 
stance from  the  nucleo-proteids,  by  the  absence  of  the  xanthin  group,  the  pyrimid.ins, 
and  the  pentose  group.  The  consistence  of  casein  from  various  species  of  animals  varies 
chemically  to  a  considerable  extent.  By  special  reactions  with  casein  anti-serum 
(precipitation,  complement  fixation),  the  caseins  from  different  species  of  animals  may 
be  differentiated  one  from  the  other.  In  the  splitting  up  of  casein  into  its  various  con- 
stituents, quantitative  differences  in  these  split  products  are  found  which  indicate  the 
differences  in  the  individual  caseins. 

The  cow  casein  contains 
according  to  C.          H.          S.          P.  N.          0. 

Tangl   52.99      6.81      0.832    0.877     15.65     23.141% 

Ellenberger  ....  53.07      7.13      0.76      0.80      15.64    22.60  % 

Burow    52.825    7.095    0.725    0.808     15.64    22.906f0 

Hammarsten  ...  52.96      7.05     ^ 0.758    0.847    15.65     

It  is  insoluble  in  water  and  in  alcohol,  but  with  bases  forms 
solutions,  the  so-called  casemates.  Alkali-caseinates  form  opales- 
cent solutions,  while  solutions  from  casemates  of  earthy  alkalies 
represent  cloudy,  milky  fluids.  Casein  is  slightly  acid,  the  solution 
of  which  with  the  bases  is  accompanied  by  the  formation  of  salt-like 
compounds. 

The  characteristics  of  casein  are  of  especial  interest,  as  they 
give  to  the  milk  its  well  known  properties  of  rennet-coagulation, 
and  easy  acid  coagulation,  etc. 

Casein  is  present  in  the  milk  as  caseinate  of  lime,  in  suspended 
condition  as  dicalcium-caseinate,  which  gives  an  acid  reaction  to 
phenolphthalein,  and  a  neutral  reaction  to  litmus. 

Acid  abstracts  calcium  from  the  caseinate,  the  casein  being 
precipitated  (that  is  casein  from  the  milk  of  cows  and  other  rum- 
inants) as  coarse,  flaky  material,  while  the  casein  from  the  milk  of 
solipeds  and  women  is  precipitated  as  a  fine,  flaky  substance. 

This  difference  in  its  properties  is  traceable  to  the  physical  condition  which  is  mani- 
fested by  the  casein  molecule  of  the  various  kinds  of  milk  (Fuld  and  Wohlgemut)  ;  but 
it  7iiay  also  be  the  result  of  a  variation  in  the  quantity  of  salt  and  proteid  present  in  the 
milk. 

In  the  presence  of  di-  and  tri-phosphates  the  casein  dissolves 
by  combining  with  a  part  of  the  bases,  so  that  the  neutral  and  alka- 
line phosphates  change  into  monophosphates  (Hammarsten, 
Arthus). 


Casein.  35 

Casein  is  also  soluble  in  other  salts,  but  not,  or  only  to  a  very 
slight  extent  in  NaCl,  Na2  S04,  NaN03,  KC1  and  others. 

In  the  presence  of  an  excess  of  acid  the  casein  which  is  first 
precipitated  is  again  dissolved  into  a  syrup-like  mass,  but  may  be 
again  recovered  as  casein  after  neutralization.  Neutral  calcium 
casein  suspensions  do  not  coagulate  in  boiling,  but  they  form  a 
pellicle  on  the  surface.  (The  nature  of  this  manifestation  is  not 
entirely  clear,  but  depends  probably  on  the  drying  and  transforma- 
tion of  the  casein  into  a  more  solid  form.) 

Casein  is  precipitated  even  in  the  presence  of  relatively  small 
quantities  of  acid  while  boiling  under  this  condition  changes  it 
slowly  into  a  body  not  susceptible  to  the  action  of  rennet.  In  over- 
heating and  likewise  in  boiling  and  over-heating  with  small  excesses 
of  alkali,  casein  is  split  up  through  hydrolysis. 

Even  under  the  action  of  water,  casein  is  split  up  into  a  pro- 
teid  body  which  is  coagulated  by  heat,  passes  through  a  filter  and 
is  probably  identical  with  whey  casein. 

The  latter  substance  is  formed  after  the  precipitation  of  the 
cheesy  substance,  through  the  action  of  rennet,  and  is  a  mixture  of 
reduction  products  of  the  casein  originating  through  the  action  of 
the  rennet  (Raudnitz). 

One  characteristic  property  of  casein  is  its  precipitation  by 
rennet  in  the  presence  of  earthy  alkali  salts.  The  precipitation  of 
casein  has  no  connection  with  the  action  of  the  rennet  as  such.  This 
may  occur  even  without  having  precipitation  as  a  result.  If  for 
instance  a  casein  solution  is  mixed  with  active  rennet,  and  another 
solution  mixed  with  inactive  boiled  rennet,  then  in  the  mixture  con- 
taining active  rennet,  para-casein  is  formed  without  any  action 
being  noticeable.  Only  after  the  addition  of  soluble  calcium  salts 
will  precipitation  of  the  para-casein  calcium  result  in  the  glass 
which  contains  the  active  rennet,  but  not  in  the  glass  containing 
rennet  which  has  been  inactivated  by  heating. 

In  the  change  of  casein  by  the  rennet  ferment,  there  results  in  addition  to  the 
substance  designated  as  para-casein,  another  proteid  body  free  of  phosphorus,  with  the 
properties  of  albumose,  the  whey -proteid  (Hammarsten). 

The  change  of  the  casein  to  para-casein,  and  whey  proteid  may 
be  a  splitting  up  of  the  casein,  or  it  may  depend  on  a  change  in 
the  grouping  of  the  molecules,  or  it  may  correspond  to  a  change  in 
its  physical  condition. 

The  action  of  rennet  in  the  curdling  of  milk  is  practically  the 
same  as  in  casein  solutions ;  however  it  is  influenced  by  the  other 
(dissolved)  substances,  by  the  other  proteids  and  salts,  and  pos- 
sibly also  by  the  physical  condition  of  the  fatty  emulsion. 

Curdling  with  calf  rennet  develops  in  accordance  with  definite 
laws.  In  milk  that  has  been  brought  to  low  temperatures  (refrigera- 
tor) the  action  of  the  rennet  may  be  established  by  subsequent  heat- 
ing; the  precipitation,  however,  will  not  take  place  until  the  mix- 
ture is  heated  to  37  deg.  C.  (Morgenroth.) 


36  Biological,  Chemical  and  Physical  Characteristics  of  Milk. 

Coagulation  may  not  always  appear  if  the  milk  is  immediately  heated  to  37  deg., 
which  would  indicate  that  some  of  the  rennet  is  destroyed  at  37  deg. 

If  the  same  milk  is  utilized  under  the  same  experimental  con- 
ditions, it  can  be  seen  that  the  amount  of  rennet  necessary  for  the 
coagulation  of  the  milk  is  nearly  proportionately  opposite  to  the 
length  of  time  necessary  for  the  coagulation  to  be  completed ;  this 
fact  is  expressed  by  Storch  and  Segelke  as  follows :  "The  product 
from  the  quantity  of  ferment  and  time  of  coagulation  is  constant." 

Each  kind  of  rennet  has  a  certain  strength  which  of  course  is  changeable,  and  rela- 
tive for  each  sample  of  milk.  In  strong  dilutions  of  the  rennet  the  action  does  not  corre- 
spond with  the  time  rule,  the  time  of  coagulation  becoming  continually  longer  unto 
infinity;  that  is,  coagulation  finally  no  longer  takes  place. 

The  action  of  rennet  depends  on  the  most  varied  factors, 
which  may  either  hasten  or  retard  its  action  and  influence  the 
precipitation. 

Acids  for  instance  strengthen  the  rennet  action,  likewise 
earthy  alkali  salts,  while  alkalies,  albumoses,  neutral  salts  of  high- 
er concentrations,  heating  of  the  milk,  talcum,  caolin,  and  muci- 
laginous substances  retard  the  rennet  action.  Shaking  reduces  the 
strength  of  the  rennet  if  it  is  in  solution. 

The  following  data  are  taken  from  a  work  of  Smeliansky  in  order  to  show  the  in- 
fluence of  various  additions  on  the  rennet  coagulation  of  cow  's  milk. 
It  appears  that: 

1.  Heating  the  milk  results  in  retarding  the  action.     The  longer  the  heating  lasts 
the  softer  and  smaller  are  the  flakes. 

2.  Addition  of  water  likewise  retards  the  action. 

3.  Mucilaginous  substances  retard  the  rennet  action  from  taking  place,  and  the 
flakes  formed  are  soft  and  loose.    Barley  water  especially  influences  its  consistence  while 
corn  water  principally  alters  the  time  of  coagulation. 

If  boiled  milk  is  diluted  with  equal  parts  of  a  mucilaginous  infusion  and  water,  the 
mucilaginous  portions  coagulate  more  quickly  than  the  watery  parts. 

4.  The  addition  of  soda  solution  renders  the  flakes  soft,  and  retards  coagulation. 
Milk  containing  0.5%  of  soda  is  entirely  prevented  from  coagulating  even  after  standing 
for  24  hours. 

Four  per  cent  of  table  salt  renders  the  flakes  softer.  Potassium  carbonate  acts 
the  same  as  soda  while  the  other  salts  respond  according  to  their  alkalinity. 

5.  Milk  of  lime  retards  the  action ;  chlorate  of  lime  accelerates  it.     If  boiled  milk 
for  instance  coagulates  after  6%  hours,  the  time  required  for  coagulation  after  the  addi- 
tion of  Ca  C12  is  only  8  to  15  minutes.     It  causes  the  flakes  of  raw  milk  to  become  loose 
and  soft. 

According  to  Smeliansky,  the  reaction  indicates  the  character  of  the  coagulation, 
and  the  time  required  for  it.  Sugars  exert  no  influence. 

On  the  other  hand  Reichel-Spiro  have  determined  a  slight  retarding  of  coagulation 
in  the  presence  of  a  high  content  of  cane  sugar. 

Cooking  the  milk  retards  the  process  (lowering  the  acidity  as 
a  result  of  the  loss  of  CO2  and  precipitation  of  lime  salts,  Eaud- 
nitz).  In  overheated  milk  no  coagulation  or  only  poor  coagulation 
takes^place.  The  addition  of  water  retards  coagulation  (Weitzel), 
likewise  physiological  salt  solution  or  whey  which  is  free  of  ren- 
net (Reichel-Spiro).  Hammarsten,  Lorcher,  Peters,  Weitzel, 
Gerber  and  Eaudnitz  conducted  experiments  relative  to  the  action 
of  salts  on  coagulation,  the  results  of  which  according  to  Eaudnitz 
may  be  interpreted  as  follows : 


Rennet.  37 

1.  The  chemical  reaction  of  rennet  is  hastened  by  the  distri- 
bution of  the  rennet  and  its  quantitative  relation  to  the  casein,  pos- 
sibly also  by  elevated  temperatures  up  to  an  unknown  limit.    Alka- 
line earths  and  acids  probably  act  in  a  similar  manner  by  activat- 
ing the  rennet. 

2.  The  chemical  reaction  is  retarded :    (a)  By  the  destruction 
of  the  rennet:  temperatures  over  41°  C.,  free  hydroxylions ;  (b)  by 
inactivation  of  the   same:   anti-rennet;     (c)    by  changes  of  tho 
casein :  temperatures  over  80  deg. ;  formalin. 

3.  The  physical  reaction  is  hastened  by  higher  temperatures, 
free  hydrogenions,  and  the  neutral  salts  up  to  a  certain  concentra- 
tion, especially  the  salts  of  alkaline  earths. 

4.  The  physical  reaction  is  retarded  by  reducing  the  concen- 
tration of  the  mentioned  salts  below  a  certain  point,  especially  of 
the  alkaline  earths ;  therefore  heating  the  milk  and  the  salts  which 
precipitate  lime,  and  calciumions  will  produce  this  result.    Higher 
concentrations  of  neutral  salts  have  the  same  effect.    It  may  also  be 
possible  that  some  of  the  alkaline  action  should  be  considered  here. 

It  is  known  that  by  the  injection  of  rennet  into  an  animal  an 
anti-rennet  may  be  produced.  The  rennet  acting  as  antigen 
induces  in  the  body  of  the  rabbit  the  formation  of  a  specifically 
acting  anti-body,  which  works  against  the  action  of  the  antigen  in 
the  re-agent  glass,  very  likely  through  fixation.  Normal  serum 
also  contains  rennet-inhibiting  substances. 

The  action  of  the  rennet  may  be  inhibited  or  entirely  prevented  by  the  addition  of 
horse  blood  as  has  been  proved  by  Hammarsten,  and  later  by  Roden.  The  same  inhibi- 
tion is  exerted  on  the  action  of  trypsin  and  pepsin  and  is  referred  to  as  an  anti-ferment 
action  of  the  blood  serum.  Blood  of  cattle  added  to  cow's  milk  also  shows  this  char- 
acteristic (Schern).  Inhibition  action  is  traced  back  to  the  anti-ferment  substances  of 
a  specific  nature  contained  in  the  blood,  and  the  presence  of  an  anti-rennet  is  considered 
probable.  It  should  however  be  noted  that  Eaudnitz  and  Jakoby  prevented  inhibition 
by  neutralizing  the  serum  with  acid. 

The  strength  of  the  rennet  may  be  tested  in  various  ways. 
That  quantity  of  milk  is  measured  which  is  coagulated  by  one  part 
of  rennet  in  40  minutes  at  35  deg.  Market  rennet  has  a  strength 
of  1:10,000  to  1 :100,000  (fluid  rennet  and  solid  rennet). 

Meunier  ascertains  the  quantity  of  milk  which  is  coagulated  by  one  c.  c.  of  undi- 
luted gastric  juice  in  ten  minutes.  Schern  employs  solutions  of  rennet  (standard  rennet 
prepared  according  to  Morgenroth)  of  varying  density  (1:100:200:300,  etc).  One  part 
of  these  rennet  dilutions  is  mixed  with  nine  parts  of  milk,  so  that  milk-rennet  dilutions 
of  1:1000:2000:3000,  etc.  are  obtained.  After  an  action  of  two  hours  the  samples  are 
placed  in  the  incubator.  The  dilutions  in  which  coagulation  may  now  be  demonstrated 
give  the  relative  value  of  the  rennet  for  the  respective  milk,  and  if  a  mixed  milk  of 
healthy  animals  had  been  used  it  establishes  the  "  rennet-titer. " 

It  is  to  be  regretted  that  the  standard  rennet  solutions  are  not 
constant,  and  that  they  weaken  by  storing,  etc.  For  this  reason  it 
is  necessary  to  establish  the  rennet-titer  before  each  test  on  the  milk 
of  healthy  animals,  or  on  casein  solutions. 

In  addition  to  the  rennet  of  calves,  extracts  and  ferments  from  other  organs  of  these 
animals  act  on  milk  in  a  similar  manner,  such  as  extracts  of  spleen,  kidney,  liver,  lung, 
thymus,  intestine,  ovaries,  testicles  and  muscles.  Rennet  from  the  stomach  of  a  calf  is 
known  as  chymosin ;  rennet  from  the  stomach  of  a  hog,  and  from  the  gastric  juice  of  man 
as  parachymosin  (Bang).  Rennet  enzymes  may  also  be  demonstrated  in  the  bodies  of 
other  animals,  fish,  birds  and  snails. 


gg  Biological,  Chemical  and  Physical  Characteristics  of  Milk. 

Enzymes  with  the  action  of  rennet  have  been  found  in  various  plants  and  parts 
of  plants,  such  as  the  artichoke,  branches  of  fig  trees,  candytuft  (Iberis  pinnata), 
yellow  mustard  (Isatis  tinctoria),  etc.,  also  in  bacteria  (proteolytic)  and  in  yeast. 

The  individual  kinds  of  rennets  vary  considerably  in  their  sensitiveness  to  various 
influences. 

Whereas  the  rennet  of  calves  is  very  susceptible  to  heat,  and  exerts  its  action 
readily  in  alkaline  solutions,  the  parachymosin  is  less  influenced  by  the  harmful  action 
of  heat,  but  is  greatly  affected  in  its  action  by  the  presence  of  alkalies. 

The  rennet  enzymes  obtained  from  plants  act  in  an  optimal  way  at  high  tem- 
peratures (sykochymas  at  65-70  deg.  C.  for  raw,  at  85  deg.  C.  for  sterilized  milk). 

Aside  from  casein,  milk  contains  proteids  which  are  coagulable 
by  heat. 

(1)  Lactalbumin  which  is  related  to  the  serum  albumin  but  is 
not  identical  with  it  (it  has  a  slight  optical  polarization: — 36.4  to 
—38  against— 60.1  to  —62.6,  Sebelien). 

(2)  Lacto-globulin  may  be  precipitated  with  the  aid  of  mag- 
nesium sulphate.    It  is  contained  in  milk  in  quantities  of  about  0 . 1 
per  cent,  of  the  total  proteids.    The  lacto-albumin  is  obtained  from 
the  residual  solution  after  saturation  with  magnesium  sulphate  and 
acidifying  it,  or  by  almost  complete  saturation  with  ammonium  sul- 
phate. 

3.  Lacto-mucin  has  been  also  demonstrated  in  milk  by  Storch,  Siegfeld,  Voltz 
and  Eosengren,  whereas  other  proteid  substances  such  as  albumose,  peptone,  albuminose, 
lacto-protein,  gelatin,  galactozymase  and  opalisin,  are  considered  more  recently  as 
products  of  the  preparation  of  other  proteid  bodies,  at  least  so  far  as  their  appearance 
in  ripe  milk  is  concerned. 

The  proteids  which  remain  in  the  fluid  after  precipitation  with 
acid  and  boiling  are  collected  under  the  term  "lacto-protein." 

The  milk  fat  consists  of  a  mixture  of  triglycerides,  choles- 
terin,  lecithin,  and  a  coloring  substance,  and  distinguishes  itself 
considerably  from  the  fat  of  the  body  and  from  the  nutritive  fat 
by  its  chemical  and  physical  characteristics.  Although  the  milk 
fats  manifest  considerable  dependence  upon  the  nutritive  fat,  as 
will  be  seen  from  the  later  chapters,  nevertheless  a  transition  of 
the  nutritive  fat  into  milk  fat  cannot  be  asserted.  The  same  state- 
ment would  also  apply  to  the  transition  of  body  fat,  although  in 
this  instance  a  closer  relationship  between  the  substances  must  be 
admitted. 

It  is  possible  that  transitory  relations  exist,  by  means  of  which  split  up  body 
fat  may  be  converted  in  the  milk  gland  into  milk  fat,  and  thus  the  nutritive  fat 
takes  part  indirectly  in  the  formation  of  milk  fat  after  first  having  been  deposited 
as  body  fat. 

It  should  be  considered  however,  that  the  specific  activity  of  the  cell  builds  up 
the  fat  from  the  constituents  at  hand,  and  utilizes  whatever  material  is  placed  at  its 
disposition,  such  as  nutritive  fat,  when  such  is  present,  or  body  fat  in  emergencies. 
The  product  will  approach  in  its  properties  the  material  which  has  been  utilized,  but 
will  always  remain  peculiar  to  the  species  of  animal  producing  it. 

A  formation  of  fat  from  proteid  is  possible,  as  may  be  seen 
when  cows  are  fed  with  substances  free  of  fat,  and  after  the  body 
fat  deposits  have  been  used  up.  It  is  probable  that  the  carbohy- 
drates of  the  food  here  take  part  in  the  formation  of  fat. 


Fat  Content.  39 


The  fat  which  is  contained  in  milk  in  the  form  of  very  fine 
globules,  causes  in  part  the  white  color  of  the  milk  through  the 
reflection  of  light.  The  size  of  the  fat  globules  varies  in  the  milk  of 
the  same  cow  and  depends  upon  the  individual,  length  of  the  period 
of  lactation,  the  race,  feeding,  and  upon  whether  the  first,  middle 
or  the  last  part  of  the  milking  is  examined.  According  to  Woll, 
D'Hunt,  Schellenberger  and  Gutzeit  the  diameter  varies  between 
0.8  and  22  n  with  an  average  of  2.2:2.5:2.9:3.6  /*. 

Variations  in  the  percentage  of  fat  are  caused  by  change  of 
food,  etc.  These  changes  also  have  an  influence  on  the  size  of  the  fat 
globules,  and  according  to  Woll  the  fat  globules  become  larger  with 
dry  feeding,  a  statement  which  could  not  however  be  confirmed 
by  Schellenberger  and  Pankowsky.  According  to  the  investigations 
of  these  authors  the  feeding  of  green  forage,  especially  clover, 
produces  large-sized  fat  globules. 

The  length  of  the  period  of  lactation  should  be  considered  since 
the  variations  of  size  at  the  beginning  of  lactation  are  more  con- 
siderable than  in  ripe  milk,  in  which  the  milk  globules  appear  more 
uniform  and  mostly  of  medium  size. 

In  colostrum  they  vary  from  the  sizes  of  dust  to  20/j.  and  over.  Donne  and 
Schulz  found  that  colostrum  contains  large,  broad  oil  drops  in  addition  to  the  small 
and  minute  fat  globules,  which  show  a  less  uniform  appearance  and  contour,  when 
compared  with  the  usually  spherical  fat  globules  of  ripe  milk. 

In  interrupted  milking  the  size  of  the  milk  globules  bears  a 
certain  relation  to  the  fat  content.  With  the  increased  quantity 
of  fat  which  obtain  in  the  milk  toward  the  end  of  a  single  milking, 
the  size  of  the  fat  globules  also  become  larger  (Schellenberger, 
Woll). 

With  the  extension  of  the  lactation  period  the  size  of  the  fat 
globules  decreases,  but  their  number  increases. 

According  to  Gutzeit  and  Schellenberger  the  following  values  were  obtained  in 
milk  from  different  breeds: 

Si?e  in  1/1000  mm.        No.  per  cc.  in  millions. 
Gutzeit :  Schellenberger : 

Voigtlander    2.73  1944      to  4476.9 

Jersey    3.5  2.95  2064.1  to  4643.3 

East   Friesian    2.30  2521.0  to  5911.0 

Angus    2.95  2.20  2886.0  to  6200.0 

Simmenthal    2.56  2995.0  to  5210.3 

Dessau     3070.0  to  6308.6 

Swiss     2.33  4008.0  to  5326.7 

Shorthorn    2.76 

Montavoner     2.62 

Holstein    2.58 

Breitenburger     2.46 

According  to  Grimmer  the  number  of  milk  globules  fluctuated  in  21  tests  on 
three  herds  of  blackish-brown  lowland  cattle  in  Pomerania,  from  1,330,000  to  3,073,000 
per  cubic  millimeter,  having  an  average  diameter  of  2.6-3.7/u. 

The  milk  globules  retain  their  form  through  their  surface 
tension  and  are  not  surrounded  by  special  capsules  which  could  be 
considered  as  membranes,  as  has  been  thought  by  former  authors. 


40  Biological,  Chemical  and  Physical  Characteristics  of  Milk. 


Although  the  milk  globules  cannot  be  entirely  freed  from  proteids  by  washing 
(covering  the  milk  with  water  and  allowing  the  separation  of  fat),  the  demonstration 
of  the  remains  of  proteids  cannot  be  considered  as  proof  of  an  actual  "haptogen  mem- 
brane" which  must  be  broken  down  during  the  butter-making  process,  in  order  to  make 
possible  the  flowing  together  of  the  milk  fat,  but  it  does  constitute  a  proof  that  rem- 
nants of  proteids,  even  after  the  most  careful  washing  of  the  cream,  remain  around 
the  fat  globules.  At  least  it  has  never  been  possible  to  demonstrate  membranes  of  the 
fat  globules,  neither  in  boiled  milk,  in  which  during  continuous  heating  larger  fat 
clumps  develop,  nor  in  fat  extractions  (Soxhlet,  Quincke,  Morres). 

Milk  sugar  is  also  a  specific  substance  of  milk.  It  is  formed 
in  the  gland  and  is  found  only  in  its  secretion.  If  sucking  is  in- 
terrupted, it  may  be  present  in  the  urine,  from  which  it  immedi- 
ately disappears  upon  amputation  of  the  lactating  gland,  or  it  may 
not  appear  at  all  when  the  gland  is  amputated  before  the  appear- 
ance of  lactation  (Sinet,  Magnus-Levy,  Zuntz).  After  the  com- 
plete removal  of  the  gland  in  goats  and  cows,  however,  a  temporary 
hyperglycosemia  and  glycosuria  appear.  If  parts  of  the  gland 
remain,  lactosuria  results. 

After  the  injection  of  glucose,  lactose  appears  in  the  urine 
(Porcher),  likewise  after  the  ingestion  of  large  quantities  of  dex- 
trose. Since  the  blood  in  the  mammary  vein  before  parturition 
and  during  lactation  contains  considerably  less  glucose  than 
the  blood  of  the  jugular  vein  (Kaufman  and  Lagne),  it  may  be 
accepted  that  glucose  has  been  utilized  in  the  gland,  and  further 
that  glucose  is  the  material  from  the  constituents  of  which  the  lac- 
tose is  formed  in  the  gland. 

Of  the  various  salts  milk  contains  compounds  of  potassium, 
calcium,  magnesium,  iron,  traces  of  manganese,  aluminum,  phos- 
phoric acid,  hydrochloric  acid,  carbonic  acid,  sulphuric  acid,  citric 
acid,  fluorine  and  iodine. 

Carbonic  acid,  oxygen  and  nitrogen  have  been  demonstrated  as 
gases  in  the  milk. 

Besides  these  substances,  lecithin,  cholesterine  and  coloring 
matter  are  present  in  the  milk,  besides  ferments  and  substances 
which  are  collected  as  residual  substances ;  these  have  been  pre- 
viously mentioned. 

Baudnitz  and  Grimmer  have  recently  published  compiled  arti- 
cles relative  to  the  individual  constituents  and  chemical  properties 
of  milk  which  contain  the  collected  material  of  many  experimental 
results,  and  at  the  same  time  show  how  much  is  still  unsettled  in 
regard  to  the  composition  of  milk  and  the  characteristics  of  the 
substances  which  it  contains. 

Certain  physical  characteristics  of  milk  correspond  to  its 
chemical  condition.  These  adjust  themselves  according  to  the  pro- 
portion of  the  various  constituents,  and  to  the  conditions  attend- 
ing the  mixing  of  the  different  component  parts. 

The  appearance  of  the  milk  is  influenced  by  the  suspended 
casein  and  the  proportion  of  fat.  Skimmed  milk,  which  is  almost 
free  from  fat  constitutes  a  non-transparent,  somewhat  bluish  fluid, 
as  compared  with  the  whitish  yellow  color  of  whole  milk.  The  ad- 


Specific  Gravity  of  Milk. 


dition  of  alkalies  to  milk  free  of  fat  renders  it  transparent.  Ham- 
marsten  furnished  the  proof  that  a  calcium  caseinate  solution  which 
corresponds  to  the  composition  of  milk  is  almost  as  non-trans- 
parent as  milk.  The  milk  becomes  less  transparent  the  smaller  the 
fat  globules  are.  This  is  most  strikingly  apparent  when  the  fat 
globules  are  broken  up  to  dust-sized  bodies  (for  instance  through 
homogenization).  The  appearance  of  fresh  milk  is  also  influenced 
by  the  coloring  matter  present  in  the  milk  plasma  and  in  the  fat. 
It  is  known  that  the  skimmed  milk  of  certain  cows  varies  considera- 
bly in  color ;  at  times  it  is  bluish  white,  sometimes  more  yellowish 
green,  again  transparent,  other  times  of  a  non-transparent  whitish 
color,  and  also  the  fat  has  a  more  yellow  color  during  the  pasturing 
of  the  animals  than  at  the  time  of  stable  feeding. 

The  non-transparency  as  mentioned  above  is  no  proof  of  the  presence  of  fat  in 
the  milk;  therefore  all  methods  which  are  destined  to  establish  the  quantity  of  fat  or 
addition  of  water  by  the  establishment  of  the  whiteness,  are  of  no  use,  as  for  instance, 
Heeren's  pioscope,  Feser's  lactoscope,  etc. 

If  milk  is  allowed  to  stand  for  a  time,  cream  forms  on  the 
surface ;  the  fat  globules  rise  and  collect  usually  as  a  distinct  layer 
of  cream  above  the  milk.  The  rapidity  of  the  separation  depends 
on  the  temperature,  the  size  of  the  fat  globules,  and  the  density  of 
the  milk  plasma.  The  quantity  of  the  cream  is  not  in  parallel  rela- 
tion to  the  quantity  of  fat ;  it  depends  on  the  size  of  the  fat  globules. 

The  separation  of  cream  may  be  hastened  and  increased  by 
centrifugalization.  During  separation  while  allowing  to  stand, 
about  85%  of  the  fat  rises  to  the  surface,  while  by  a  perfectly 
operating  centrifuge  the  separation  of  cream  may  be  accomplished 
up  to  0. 01%  of  its  fat. 

The  specific  gravity  of  the  milk  depends  on  the  solid  sub- 
stances, the  relation  of  the  mixture  and  the  condition  of  the  sus- 
pended, dissolved,  and  emulsified  constituents  of  the  solid  sub- 
stances. Corresponding  to  the  variable  composition  of  cow's  milk 
it  is  natural  that  the  specific  gravity  of  the  milk  should  vary. 
It  fluctuates  considerably,  varying  from  1.027  to  1.034  at  a 
temperature  of  15  deg.  Similar  to  the  impossibility  of  speaking  of 
milk  of  normal  composition,  one  cannot  speak  of  milk  of  normal 
specific  gravity,  and  even  to  give  average  figures  would  be  of  very 
problematical  value;  but  to  take  such  average  figures  or  even 
smallest  values  as  a  basis  for  the  calculation  of  falsification  would 
be  a  gross  error.  Milk  from  many  cows  would  under  ordinary  con- 
ditions have  a  specific  gravity  of  1,029  to  1,033. 

The  specific  gravity  is  measured,  or  is  calculated  from  the 
values  of  fat  contents  and  solids,  according  to  formulas,  which, 
depending  on  the  milk  from  certain  breeds,  or  certain  localities, 
show  slight  variations.  This  formula  made  on  the  basis  of  the 
value  of  the  specific  gravity  of  the  milk  fat  (about  0.93),  and  the 
solids  or  dry  substances  (1.6001),  which  is  quite  constant,  is 
according  to  Fleischmann : 


42  Biological,  Chemical  and  Physical  Characteristics  of  Milk. 

1000 

B==  • 


1000—3.75  (d—  1.2  f) 

In  these  equations  s  stands  for  specific  gravity,  d  for  dry 
substances  or  solids,  and  f  for  fat. 

The  following  values  may  also  be  calculated  from  the  fat  con- 
tents of  the  milk  and  its  specific  gravity. 

1.  Total  solids: 

d=1.2f+2.665X100s-10° 

s 

2.  The  fat-free  solids  are  shown  by  deducing  the  percentage 
of  fat  from  the  percentage  of  the  total  solids. 

3.  The  specific  gravity  of  the  solids 

sXd  _ 
"  sXd—  (100  s—  100) 

4.  Finally  the  fat  contents  when  the  solids  and  specific  grav- 
ity are  known: 


The  values  obtained  from  formulas  are  of  course  not  abso- 
lutely correct,  but  represent  the  results  only  approximately  with 
the  analytical  methods  of  weights,  the  fat-free  dry  substance  of  the 
milk  is  not  of  absolute  constant  composition,  but  varies,  so  that  its 
specific  gravity  which  is  based  upon  the  sugars,  proteids  and  salts, 
varies  more  or  less  from  the  number  which  has  been  accepted  by 
Fleischmann  as  the  average  value  (1.60). 

The  equations  hold  only  for  cow's  milk. 

If  milk  is  freshly  drawn,  and  immediately  tested  it  shows  a 
considerably  lower  specific  gravity  (0.0008-0.0015),  than  after 
cooling.  The  milk  "contracts"  and  becomes  constant  in  its  specific 
gravity  only  after  standing  for  several  hours.  The  cause  of  this 
manifestation  is  not  yet  entirely  clear.  Toyonaga  aims  to  explain 
it  by  the  fixing  of  previously  uncooled  and  fluid  fat  globules,  which 
is  the  most  plausible  explanation  ;  other  authors  believe  that  the 
contraction  is  the  result  of  a  cessation  of  the  expansion  of  the 
casein. 

The  density  of  the  milk  varies  in  accordance  with  the  tempera- 
ture. The  maximum  (for  water  at  4  deg.)  lies  almost  near  its 
freezing  point,  namely  at  0  .  3  deg.  C. 

The  freezing  point  of  milk  is  somewhat  lower,  namely  —  0  .  54 
to  —  0  .  57  deg.  This  is  especially  influenced  by  the  presence  of  salt, 
less  by  the  sugar  contents  of  the  individual  samples  of  milk,  and 
it  is  induced  by  the  relatively  constant  amount  of  soluble  salts 
in  the  salt  contents,  which  is  subject  to  only  slight  fluctuations  in 
the  milk  of  healthy  animals. 

For  the  sake  of  completeness  the  electrical  conductibiiity  of 
the  milk  should  also  be  mentioned.  This  varies  according  to  the  re- 
sistance which  is  offered  by  the  fluid  to  the  current.  It  fluctuates 


Polarization  of  Milk.  43 


within  wider  borders  than  the  freezing  point,  and  is  influenced  ac- 
cording to  Zanger  by  general  diseases,  through  local  affections  of 
the  udder,  by  estrum,  pregnancy,  feeding,  etc.  The  conductivity  is 
diminished  by  the  fat  globules ;  therefore  skim  milk  conducts  better 
than  whole  milk  or  cream.  The  conductivity  of  the  different  quar- 
ters is  inversely  proportional  to  the  quantity  of  milk,  in  milk  from 
different  quarters  of  one  cow  (Schnorf). 

The  viscosity  of  milk  is  a  factor  which  principally  depends 
on  the  condition  and  on  the  quantity  of  the  casein  and  the  fat. 
Higher  temperatures  reduce  the  viscosity,  likewise  shaking;  quiet 
standing  increases  it. 

The  surface  tension  of  milk  is  lower  than  that  of  water 
(0.053  against  0.075). 

Of  the  physical  properties  the  specific  gravity  of  milk  and  its 
serum,  and  the  polarization  of  milk  serum,  are  of  special  impor- 
tance for  the  practical  testing  of  milk  (see  technique).  For  practi- 
cal results,  however,  the  determination  of  the  fat  contents  is  also 
necessary. 

As  it  has  been  shown  the  total  solids  may  be  determined  by 
the  aid  of  the  fat  contents  and  the  specific  gravity  and  the  fat-free 
solids  may  be  established  by  deducting  the  percentage  of  fat, 
these  four  factors  are  generally  sufficient  for  the  preliminary 
tests.  For  more  accurate  study  these  preliminary  tests  are  com- 
pleted by  the  establishment  of  the  specific  gravity  of  the  milk 
serum,  or  still  better  by  the  ref  ractoscope  to  determine  the  chlorids 
of  calcium  serum,  which  renders  more  rapid  work  possible.  This 
is  a  method  whose  satisfactory  use  in  practice  has  been  proven  by 
the  numerous  works  of  Mai  and  Eothenfusser. 

Publications  relative  to  the  polarization  of  milk  were  issued 
by  Valentin  in  1879,  and  later  continued  by  Villiers  and  Bertault, 
Braun,  Utz,  Lam,  Radulesku,  Eipper,  Schnorf  and  others,  on  ren- 
net serum,  acetic  acid  serum  and  milk  serum,  which  had  been  pre- 
pared by  voluntary  coagulation. 

The  given  values  of  the  authors  varied  in  accordance  with  the 
method  of  preparation  of  the  serum ;  nevertheless  it  could  be  estab- 
lished that  comparatively  uniform  figures  were  obtained  whenever 
the  work  was  carried  out  under  similar  experimental  conditions. 
In  1908  Cornalba  showed  that  contrary  to  the  variance  in  the 
amount  of  colloidal  substances  dissolved  or  suspended  in  milk,  the 
sum  of  the  dissolved  constituents  of  milk  is  very  constant. 
Whereas  in  samples  of  mixed  milk  the  sum  of  the  first  substances 
varied  between  5  and  8.585  per  cent,  the  differences  for  the  total 
dissolved  substances  were  only  6.05  to  6.25  per  cent. 

Milk  serum  which  contains  the  dissolved  substances,  offers 
therefore  constant  results  in  the  examinations,  the  same  as  the 
examinations  which  lead  to  the  establishment  of  the  fat-free 
solids,  which  still  include  the  casein.  Examinations  of  serum 
are  therefore  of  the  highest  practical  value  for  the  demonstration 


44 


Biological,  Chemical  and  Physical  Characteristics  of  Milk. 


or  establishment  of  the  addition  of  water,  provided  that  the  serum 
is  always  prepared  in  the  same  way.  Ackermann,  Mai  and  Roth- 
enfusser have  in  their  fundamental  works,  determined  the  practi- 
cal importance  of  the  polarization  of  the  proteid-free  serum,  and 
have  proved  that  with  the  polarization  of  the  chloride  of  calcium 
serum  we  possess  means  which  are  better  adapted  than  any  other 
to  the  detection  of  the  adulteration  of  milk  by  water.  Refrac- 
tion is  the  most  valuable  accessory  to  the  various  methods  of  tests 
of  recent  times. 

Ackermann  found  in  2,800  samples  of  normal  milk,  variations 
in  the  scale  division  of  Zeiss  's  immersion  ref ractometer,  from  38 . 5 
to  40.5. 

Even  slight  additions  of  water  reduce  the  refraction  con- 
siderably; the  addition  of  5%  of  water  results  in  a  1.3  lowering  of 
the  scale  division,  while  10%  lowers  it  2.3. 

According  to  Mai  and  Rothenfusser  the  original  refraction  of 
39  scale  divisions  is  lowered  to  a  refraction  of : 

37.9  with  about    4%  addition  of  water 
37.7     "        "         5%         "         < 


37.5 

37.3 

37.1 

36.9 

36.7 

36.5 

36.3 

36.1 

35.9 

35.7 

35.5 

35.3 

35.1 

35.0 

34.8 

34.0 

33.3 

32.6 

32. 

30.9 


070 

7% 
8% 

10% 
11% 

12% 
13% 

14% 


16% 

17% 
18% 
19% 
20% 
25% 
30% 
35% 
40% 
50% 


It 
(t 

1 1 
14 

1 1 
(t 

1 1 
1 1 
1 1 
« 
i  I 
1 1 
t  < 
(4 
it 
it 
it 
1 1 
<  t 
1 1 
( l 


In  the  establishment  of  the  refraction  index  of  the  chloride  of 
calcium  serum  it  was  also  discovered  that  it  is  impossible  to  estab- 
lish normal  values  for  the  chloride  of  calcium  serum,  as  well  as  for 
other  constituents  of  milk.  Mai  and  Rothenfusser  also  estab- 
lished the  general  rule  for  milk,  that  only  in  the  presence  of  rigor- 
ous controls  of  the  same  origin  can  the  addition  of  water  be 
satisfactorily  determined,  and  the  extent  of  the  adulteration 
established. 


Ferments  in  Milk.  45 


The  experiments  of  Weigner  and  Yakuwa  are  of  interest  since 
they  demonstrate  that  the  refraction  and  specific  gravity  of  the 
chloride  of  calcium  serum  are  theoretically  of  equal  value.  Mai 
and  Rothenfusser,  on  the  other  hand,  emphasize  the  fact  that  of 
two  theoretical  methods  of  equal  value  the  man  in  practice  has  to 
prefer  the  method  which  offers,  with  the  same  certainty  of  the 
results,  greater  advantages  in  regard  to  rapidity,  convenience, 
and  saving  of  material,  advantages  which  the  method  of  refrac- 
tion possesses. 

The  investigations  of  Mai  and  Rothenfusser  prove  that  the 
variations  in  the  results  of  continued  tests,  from  day  to  day  may 
reach  in  mixed  milk  of  one  stable  0.1  to  0.55,  and  in  longer  periods 
( 22  days ) ,  up  to  1 . 0.  Changes  of  feeding  have  no  marked  influence. 
The  milk  of  individual  cows  failed  to  show  any  important  fluctua- 
tion during  the  time  in  which  the  tests  of  the  entire  stable  were 
made  (0.2  to  0.6). 

More  considerable  may  be  the  fluctuation  between  the  find- 
ings of  normal  milk  and  the  secretion  from  cows  with  an  affected 
udder,  and  the  variation  between  the  findings  of  milk  from  the 
same  animal  while  healthy,  and  within  24  hours  after  the  udder 
becomes  diseased. 

The  milk  of  individual  animals  with  affected  udders  shows, 
not  infrequently,  values  which  are  considerably  below  the  values 
of  normal  milk.  This  has  been  proved  by  the  work  of  Metzger, 
Fuchs,  Jesser  and  Henkel,  and  from  the  experience  of  the  official 
milk  control  station. 

These  abnormal  values,  however,  do  not  affect  the  worth  of 
this  method,  if  the  results  are  compared  through  the  use  of  satis- 
factory control  tests,  and  confirmed  by  other  methods. 

Ferments  in  Milk.    Immune  Bodies. 
Milk  as  Antigen. 

For  the  testing  of  milk  special  characteristics  which  it  pos- 
sesses, which  may  be  collected  under  the  name  of  reaction  manifes- 
tation of  ferment  action,  and  for  which  at  present  there  is  still 
no  satisfactory  explanation,  are  of  importance. 

Under  the  term  ferments  (enzymes)  those  substances  are 
included  which  hasten  chemical  changes  with  an  explosion-like 
rapidity  (Uexkuell),  and  without  using  themselves  up  they  act  in 
relatively  minimal  quantities.  Their  activity  is  inhibited  by  the 
products  of  the  reaction.  Higher  degress  of  heat  and  certain 
toxins  (ferment  toxins,  as  for  instance  hydrocyanic  acid)  inhibit 
their  activity,  the  ferments  being  thermolabile.  The  author  desig- 
nates as  ferments  all  of  those  bodies  with  ferment-like  action,  with- 
out consideration  as  to  whether  the  nature  of  the  ferment  is  known 
or  not. 

A  careful  distinction  must  be  made  between  original  fermen- 


46  Biological,  Chemical  and  Physical  Characteristics  of  Milk. 

tative  action  and  ferment-like  bacterial  activity  sometimes  taking 
place  in  milk. 

The  original  "ferments,"  the  nature  of  which  is  disputed, 
originate  from  the  blood,  or  are  formed  from  the  cells  of  the  blood 
and  the  parenchyma  of  the  udder.  They  are  either  eliminated  the 
same  as  products  of  metabolism  into  the  surrounding  parts,  or 
they  are  anchored  to  the  cell  and  are  only  set  free  in  the  breaking 
up  of  the  cell  (ecto-  and  endo-ferments).  The  ferments  in  their 
action  are  destined  to  certain  substances  to  which  they  fit,  "as  the 
key  fits  the  lock"  (Fischer).  They  act  either  through  hydrolytic 
splitting,  through  oxidation,  or  through  reduction. 

Those  ferments  are  of  importance  to  the  milk  inspector,  where 
diminished  or  increased  presence  or  complete  absence  offers  cer- 
tain conclusions  as  to  various  conditions  in  the  udder  or  in  the 
milk.  These  are  the  amylase  (diastase),  the  indirect  oxydase  (per- 
oxydase),  the  superoxydase  (catalase)  and  the  indirect  reductase 
( aldehydreductase,  ' l  aldehydcatalase  " ) . 

Besides  those  mentioned,  milk  also  contains  other  bodies  which  are  included  among 
the  ferments;  for  practical  milk  examinations,  however,  they  have  little  or  no  bearing. 
Mention  need  only  be  made  here  of  the  proteolytic  ferment,  ' '  Galactase, ' '  found  by 
Babcock  and  Eussell  and  bodies  acting  like  pepsin  or  trypsin  (Jensen,  Freudenreich, 
Spolverini  and  others).  These  are  only  present  in  very  small  amounts.  Kinase  and 
fibrin  ferment  have  also  been  demonstrated  in  milk. 

The  proteolysis  could  be  explained  through  the  presence  of  leucocytes  in  the  milk. 
Similar  to  the  proteolytie  ferments  which  cannot  be  utilized  for  diagnostic  purposes, 
the  lipase  and  the  salol-pplitting  salolase  (the  existence  of  which  as  a  ferment  is  dis- 
puted by  Desmouliere,  Miele  and  Willen;  the  alkaline  reaction  of  various  kinds  of  milk 
is  sufficient  to  split  up  the  salol)  can  not  be  likewise  utilized  for  the  purpose  of  di- 
agnosis. Rullmann  in  1910  proved  by  the  examination  of  aseptically  drawn  milk,  that 
salolase  is  not  an  original  ferment;  the  author  considers  the  splitting  of  the  salol  to  be 
the  result  of  bacterial  action. 

Of  the  ferments  in  milk  which  split  up  the  carbo-hydrates,  the 
amylase  (diastase,  galactoenzyme),  whose  action  is  similar  to  the 
ptyalin  of  saliva  splitting  up  the  polysaccharid  starch  into  dex- 
trose and  maltose,  is  of  the  greatest  interest  (Moro).  This  fer- 
ment was  first  found  by  Bechamp  in  the  milk  of  women,  later  by 
Zaitscheck,  Koning,  Seligmann  and  others  in  cow's  milk.  One 
hundred  c.  c.  of  mixed  milk  can  be  split  up  by  0.015  to  0.020  gm.  of 
amylase.  Amylase  is  destroyed  by  heating  for  30  minutes  at  68 
deg.  C.  (Koning) ;  the  optimum  of  its  activity  lies  at  45  deg.  C. 

The  substances  designated  as  oxydase  and  peroxydase  exert  a  special  action.  They 
transmit  the  oxidation  either  by  "activation  of  the  oxygen  of  the  air,"  (direct  oxida- 
tion) or  by  abstracting  the  active  oxygen,  for  instance  from  peroxide  of  hydrogen  (per- 
oxydase). Substances  acting  as  reagents  indicate  their  oxidation  by  the  formation  of 
coloring  matter. 

The  occurrence  of  direct  oxydase  in  milk,  the  action  of  which 
appears  even  without  peroxide  of  hydrogen,  is  uncertain.  Bull- 
man  has  found  traces  of  direct  oxidation  in  milk  drawn  under 
sterile  conditions ;  the  quantity  however  is  almost  nil  for  practical 
purposes. 

The  indirect  oxydase  acts  only  after  the  addition  of  hydro- 
gen peroxide  or  other  oxygen  carriers  (for  instance  super-borates), 


Catalase.  47 

by  abstracting  active  oxygen  after  the  formula  H202=H20+0 
(Jensen).  The  active  oxygen  oxidizes  the  added  "chromogenic" 
substances,  as  guaiacol,  ursol,  paraphenylendiamin,  etc.,  to  coloring 
matter.  The  peroxydase  is  injured  by  long  heating,  even  at  the 
relatively  lower  temperature  (50-60-70  deg.  C.),  and  is  destroyed 
at  about  75  deg.,  so  that  boiled  or  pasteurized  milk  may  be  dis- 
tinguished from  raw  milk  by  the  non-appearance  of  the  color 
reaction. 

The  action  of  the  superoxydase  (Raudnitz)  or  catalase 
(Loew)  develops  in  a  different  way.  It  splits  the  H202  according 
to  the  formula  2  H202=2  H20+20,  which  join  to  a  molecule  of  02. 
Other  authors  include  the  superoxydase  with  the  oxidizing  fer- 
ments, as  the  freed  oxygen  is  utilized  in  the  body  for  the  oxidation 
(Seligmann).  According  to  others  it  is  included  with  reductase, 
as  the  action  of  the  ferments  on  H202  equals  a  reduction  of  2  H20, 
and  molecular  oxygen  02  which  passes  out  without  being  utilized 
for  oxidation,  whereas  the  oxygen  freed  by  peroxydase  is  imme- 
diately utilized  for  further  oxidation  changes;  therefore  the  per- 
oxydase is  an  oxidyzing,  while  the  catalase  is  a  reducing  ferment 
(Grimmer). 

Original  catalase  has  been  demonstrated  in  the  milk  of  all 
animals ;  it  originates  in  the  cells  of  the  milk  gland,  especially  from 
the  leucocytes.  It  is  secreted,  but  may  be  set  free  in  the  breaking 
down  of  cells  or  may  appear  bound  to  the  cell.  That  catalase  is 
derived  from  the  cells  (especially  leucocytes)  is  not  contradicted 
by  the  fact  that  cream  is  richer  in  catalase  than  skim  milk  since 
leucocytes  and  other  cells  are  also  included  in  the  separation  of 
the  cream.  These  conditions  were  indicated  by  Friedjung,  Hecht 
and  Pallazzi,  and  later  confirmed  by  Koning.  This  also  explains 
the  reason  for  the  centrifuge  foam,  rich  in  leucocytes,  giving  such  a 
strong  reaction.  Since  the  formed  elements  (cells)  are  precipitated 
with  the  casein,  and  probably  a  part  of  the  free  ferment  is  also 
drawn  down  with  it,  milk  serum  is  always  poorer  in  catalase  than 
the  original  milk. 

Catalase  passes  through  infusorial  earth  filters,  but  consider- 
able quantities  are  retained.  Light,  storage,  etc.,  affect  catalase, 
even  if  it  is  relatively  resistant.  A  leucocytic  extract,  which  was 
kept  exposed  to  the  light  in  the  laboratory  of  the  author,  showed 
even  after  months,  an  unweakened  action  to  H202,  while  hydrogen 
sulphide,  hydrocyanic  acid,  potassium  cyanide,  mercuric  cyanide, 
barium  nitrate,  hydrochloric  acid,  sulphuric  acid,  acetic  acid, 
oxalic  acid,  and  potassium  nitrate  affected  its  action  (Faitelowitz). 
It  appears  noteworthy  that  H202  inhibits  the  ferment  in  its  action. 
In  the  presence  of  excessive  amounts  of  peroxide  of  hydrogen  the 
ferment  splits  up  less  H202  than  if  the  diluted  peroxide  of  hydro- 
gen is  gradually  added. 

Heating  to  62-70°  C.  destroys  the  original  catalase  in  a  short 
time.  The  optimum  temperature  appears  to  be  about  37  deg.  C. 


48  Biological,  Chemical  and  Physical  Characteristics  of  Milk. 

An  original  " ferment,"  the  nature  of  which  is  by  no  means 
definite,  is  Schardinger's  formalin  methylene  blue  reductase,  which 
according  to  Trommsdorff,  will  be  designated  as  Schardinger's 
ferment  (synonyms  are  indirect  reductase,  aldehydcatalase,  alde- 
hydreductase).  Fresh  milk  in  a  mixture  of  formalin  and  aqueous 
methylene  blue  solution  (Schardinger's  re-agent),  is  decolorized 
inside  of  a  few  minutes.  Smidt  explains  the  action  of  Scharding- 
er's ferment  by  the  fact  that  the  formalin  changes  into  formic  acid 
and  thereby  reduces  the  methylene  blue.  The  character  of  its 
action  however  is  not  yet  solved.  The  Schardinger  ferment  exerts 
its  best  action,  at  65  to  70  deg.  C.,  it  is  destroyed  above  70  deg.  As 
has  already  been  indicated  by  Smidt  and  confirmed  by  Tromms- 
dorff, Schardinger's  ferment  is  very  sensitive.  It  is  injured  by 
small  excesses  of  formalin,  and  by  relatively  larger  quantities  it 
is  destroyed. 

Bonier  and  Sames  established  more  recently,  the  interesting  fact  that  boiled  milk 
with  0.3  e.  c.  of  a  1%  of  ferrosulphate  solution  also  gives  the  reaction,  and  this  disap- 
pears again  when  the  mixture  is  boiled  for  a  half  hour.  The  authors  point  to  the  care 
which  must  be  taken  in  .'judging  the  so-called  enzyme  reaction,  since  it  is  possible,  with 
the  aid  of  simple  chemical  reagents,  to  produce  similar  effects  to  those  obtained  in 
the  supposed  enzymatic  reaction. 

Very  little  is  known  relative  to  the  origin  of  the  formalin  re- 
ductase in  milk.  This  ferment  is  not  in  every  sample  of  milk,  being 
frequently  absent  in  milk  from  an  animal  whose  off-spring  is  still 
sucking,  and  in  animals  which  are  just  fresh  in  milk  (Schern).  It 
is  absent  when  the  time  of  milking  is  over-extended,  and  in  stasis 
of  the  milk  (Romer  and  Sames),  and  it  does  not  decolorize,  or  only 
incompletely  so,  in  the  first  part  of  the  milking,  better  in  the 
middle  of  the  milking,  and  rapidly  in  the  last  portion  of  the  milk- 
ing. This  also  corresponds  to  the  relative  frequency  of  fat  in 
milk  but  no  one  however  has  been  able  to  establish  a  complete  par- 
allelism. The  authors  conclude  from  this  that  the  same  conditions 
under  which  the  gland  excretes  especially  large  amounts  of  fat, 
cause  the  quantity  of  Schardinger's  ferment  to  be  likewise  in- 
creased. 

Milk  as  Antigen  and  Carrier  of  Anti-Bodies. 

Since  the  fundamental  experiments  of  Ehrlich  relative  to  the 
formation  of  immune  substances  in  the  animal  body,  we  possess  an 
explanation  for  manifold  manifestations  between  the  inter-action 
of  the  disease-producing  agent  and  the  animal's  power  of  protec- 
tion, known  as  Ehrlich 's  theory  of  immunity. 

The  substances  which  are  formed  in  the  body  in  the  com- 
bat against  certain  invaders  are  the  anti-bodies ;  the  harmful  sub- 
stances which  are  capable  of  stimulating  the  body  to  the  formation 
of  anti-bodies  are  the  antigens. 

Antigens  may  be  substances  of  the  most  varied  kinds ;  animal 
proteid,  animal  cells,  plant  cells,  plant  proteid,  living  and  dead  bac- 
teria, bacterial  substances,  toxins,  etc.  The  antigens  are  distin- 


Antigen  Action.  49 


guished  by  groups,  which  make  possible  their  combining  with  cer- 
tain groups  of  the  cell  substances  of  the  body.  The  "haptophore" 
groups  of  antigens  under  certain  conditions  fit  as  a  key  fits  the 
lock,  into  the  haptophore  group  of  the  "receptors,"  thus  making 
possible  the  binding  of  the  antigens  to  the  cell.  These  terms  were 
applied  to  these  bodies  by  Ehrlich. 

The  simplest  way  of  explaining  the  mechanism  of  the  antigen 
action  and  the  anti-body  formation  is  by  using  toxin  as  an  example. 

A  toxin  is  an  antigen  with  a  haptophore  binding  group,  and  a 
poison-producing  group,  the  toxophores.  If  the  toxin  enters  the 
body  of  an  animal  it  may  find  groups  on  the  cell  to  which  it  fits, 
the  so-called  receptors,  which  bind  its  haptophore  group.  If  this 
has  been  the  case  the  toxophore  group  exerts  its  action,  the  effect 
of  the  toxin  becomes  noticeable  and  the  animal  suffers  as  a  result 
of  the  toxin.  If  there  are  no  receptors  present  for  the  specific 
toxin  it  is  impossible  for  the  toxin  group  to  exert  its  action,  and 
the  animal  is  therefore  resistant  against  this  respective  toxin. 

It  is  possible  that  as  a  result  of  the  receptors  of  the  cell  com- 
bining with  the  toxin,  the  cell  molecule  is  destroyed.  But  if  the 
damage  is  not  too  serious,  the  protoplasm  is  stimulated  to  produce 
numerous  receptors, — an  over-production  in  fact.  As  not  all  of 
these  are  necessary  for  the  performance  of  the  cell  function,  the 
superfluous  ones  are  rapidly  thrown  off  into  the  body  fluids.  If 
such  free  receptors  combine  with  the  haptophore  groups  of  the 
toxin,  the  latter  is  no  longer  able  to  combine  with  the  protoplasm 
of  the  cell.  These  free  receptors  therefore  protect  the  body  against 
renewed  action  of  the  toxin,  that  is  they  act  as  antitoxins,  and  con- 
stitute the  antitoxic  part  of  the  serum. 

Besides  the  antitoxins,  the  action  of  which  lies  principally  in 
the  neutralization  of  the  binding  group  of  the  toxin  (anti-bodies  of 
the  first  order),  there  are  still  more  complicated  receptors,  for 
instance  those  which  possess  an  active  or  ferment-producing 
group ;  they  are  anti-bodies  of  the  second  order.  Finally  there  are 
anti-bodies  of  the  third  order,  which  are  unable  to  act  by  them- 
selves, but  must  utilize  a  third  body  in  order  to  exert  an  action  on 
the  antigen. 

Immune  bodies  of  the  third  order  become  complete  in  their 
action  only  through  the  utilization  of  the  complement.  These  im- 
mune bodies  of  the  third  order  possesss  therefore  a  binding  group 
for  anchoring  the  antigen,  and  a  binding  group  for  the  complement. 
They  are  amboceptors,  in  contradistinction  to  the  uniceptors  of  the 
first  and  second  order. 

Some  anti-bodies  resist  heating  for  a  half  hour  at  56  deg.  C. ; 
they  are  thermostabile,  as  for  instance  the  antitoxins,  the  agglu- 
tinins,  the  amboceptors,  while  others,  as  for  instance  the  comple- 
ment, are  destroyed  at  this  temperature,  as  they  are  thermo-labile. 

Tf,  for  instance,  hemolytic  anti-bodies  are  produced  in  a  rabbit  by  treating  the 
rabbit  with  red-blood  corpuscles  of  another  animal,  then  the  hemolytic  rabbit  serum 
lo^es  its  action  by  heating  to  56  de^.  C. 


50  Biological,  Chemical  and  Physical  Characteristics  of  Milk. 

The  red  blood  corpuscles  however  are  again  dissolved  when  to  the  heated,  "inacti- 
vated" rabbit  serum,  guinea-pig  serum  containing  complement  is  added.  Therefore, 
whereas  neither  the  amboceptor  in  itself,  nor  the  complement  in  itself  can  dissolve 
blood  corpuscles,  the  combination  of  the  two  is  capable  of  doing  it. 

The  action  of  the  anti-body  is  specific  for  the  substance  which 
induced  its  formation,  on  homologous  antigen.  Diphtheria  anti- 
toxin acts  only  on  the  toxins  of  the  diphtheria  bacillus,  and  not  on 
the  toxins  of  the  tetanus  bacillus.  The  specificity  is  a  very  high 
one,  nevertheless  it  is  only  relative;  that  is,  a  similar,  although 
somewhat  weaker  action  is  exerted  on  related  antigen,  as  compared 
with  the  specific  antigen. 

The  chemical  structure  of  the  anti-bodies  is  unknown,  and 
they  are  generally  designated  according  to  the  action  which  the/ 
exert  in  the  animal  body. 

Anti-toxins  neutralize  toxins,  agglutinins  agglutinate  (stick 
together)  animal  cells  and  bacteria,  and  drag  them  to  the  bottom, 
precipitins  and  coagulins  produce  precipitation  in  antigen  solu- 
tions, hemolysins  dissolve  erythrocytes,  bacteriolysins  dissolve 
bacteria,  cytolysins  dissolve  animal  cells,  etc. 

If  anti-bodies  are  produced  by  injecting  antigens  into  an  an- 
imal, then  the  animal  is  actively  immunized  against  the  antigen. 
On  the  other  hand,  if  another  animal  is  injected  with  the  produced 
anti-bodies  it  is  given  a  passive  immunity.  The  active  immunity 
lasts  for  a  long  time,  the  passive  immunity  does  not  last  beyond 
several  weeks. 

If  anti-bodies  are  present  in  the  blood  in  certain  quantities 
they  are  excreted  by  the  milk  gland,  and  may  be  demonstrated  in 
the  milk. 

Ehrlich  succeeded  in  proving  the  passing  of  anti-toxins  into 
the  milk  of  anti-toxic  immune  mothers,  by  showing  that  young 
mice  from  non-immune  mothers  acquired  a  high  degree  of  resis- 
tance against  the  toxin  when  they  were  allowed  to  suck  actively- 
immunized  mothers. 

The  passing  of  anti-bodies  into  the  milk  even  in  the  presence 
of  passive  immunity  was  proven  by  Ehrlich,  Schmidt  and  Pflanz, 
although  the  passage  was  only  slight.  The  action  of  such  milk  was 
15  to  20  times  weaker  than  that  of  the  blood. 

Similar  to  the  action  of  the  anti-bodies  of  the  first  order  are 
those  of  the  uniceptors  of  the  second  order;  for  instance,  bacterial 
agglutinins  and  precipitins.  The  passage  of  agglutinins  from  the 
blood  into  the  milk  has  been  demonstrated  by  Kraus,  in  goats  which 
had  been  immunized  against  colon-bacilli,  typhoid  and  cholera. 
The  later  works  of  Bensaude,  Bertarelli,  Bamberg  and  Briigsch,  de 
Blasi,  Courmont,  Cade,  Figari,  Maragliano,  Eodella,  Staubli  and 
others  confirm  the  findings  of  Kraus.  The  agglutination  value  of 
milk,  as  compared  with  blood,  may  be  lower  or  identical,  or  it  may 
even  be  greater  than  that  of  the  blood.  As  it  has  been  found  that 
bacterial  agglutinins  may  pass  into  the  milk,  so  it  also  has  been 
proved  that  agglutinins  against  animal  cells  may  do  likewise. 


Complement  Content  of  Milk. 


That  under  certain  conditions  amboceptors,  as  immune  bodies 
of  the  third  order,  may  pass  into  the  milk,  is  proved  by  Bertarelli's 
experiment  on  a  sheep  treated  with  the  red  blood  corpuscles  of  a 
chicken.  The  specific  hemolytic  amboceptor  which  resulted  could 
be  demonstrated  in  the  milk.  Therefore  although  amboceptors 
may  pass  into  the  milk  and  although  normal  milk  contains  non- 
specific hemolytic  amboceptors  in  small  amounts,  nevertheless  the 
passing  of  hemolysins  into  the  milk  is  very  uncertain.  According 
to  Kraus,  Kopf  and  others  hemolysins  do  not  occur  in  milk  ;  like- 
wise bacteriolysins  are  absent,  or  their  presence  is  very  doubtful, 
according  to  the  investigations  of  Bab.  Of  course  one  of  the 
hemolytic  factors,  the  amboceptors,  might  be  present  in  the  blood, 
while  the  complement  under  the  special  conditions  present  in  milk, 
may  be  inactive. 

While  Pfaundler  and  Moro  state  that  hemolytic  and  bacterici- 
dal complement  may  be  found  in  cows'  milk,  Bauer  and  Kopf,  and 
Bauer  and  Sassenhagen,  on  the  other  hand  showed  that  in  normal, 
ripe  milk  complements  are  not  present;  that  is,  even  by  special 
examinations  only  traces  could  be  established. 

On  the  contrary  in  samples  of  colostral  milk,  and  milk  from 
udders  affected  with  mastitis,  both  amboceptor  and  complement 
may  be  demonstrated. 

The  complement  content  of  milk  drops  with  the  duration  of 
time  which  has  elapsed  between  parturition  and  the  taking  of  the 
sample,  until  from  the  sixth  to  the  twenty-seventh  day  after  calving 
the  amount  of  the  complement  disappears. 

This  observation  may  possibly  be  of  great  practical  value  in 
ascertaining  whether  or  not  a  cow  is  fresh  in  milk.  Mastitis  milk, 
which  bears  a  close  relation  to  colostral  milk,  showed  a  relative 
richness  in  amboceptor  and  in  complement,  thereby  making  it  pos- 
sible to  establish  the  affection  of  the  udder  by  the  demonstration 
of  the  complement.  Of  course  it  is  not  certain  that  the  comple- 
ment occurs  early  enough  to  enable  this  method  to  be  utilized  more 
readily  than  for  instance  the  Trommsdorff  test,  the  catalase  test, 
or  microscopic  examination  of  the  centrifuged  sediment,  and 
others. 

Sassenhagen  found  in  one  case  that  the  presence  of  mastitis 
could  be  determined  by  complement-fixation  18  days  before  the 
first  clinical  appearance  of  the  disease,  even  when  the  quantity 
of  sediment,  after  the  Trommsdorff  reaction  was  insufficient  to 
afford  a  basis  for  a  diagnosis  of  mastitis. 

Bauer  further  proved  that  complement  inhibiting  substances 
are  present  in  milk  ;  Hausmann  and  Pascucci  traced  this  inhibition 
of  hemolysis  to  the  presence  of  lecithin  or  cholesterin  in  the  milk. 

According  to  Kopf  the  complement  passes  from  the  colostral 
milk  into  the  blood  of  the  calf  ;  it  may  be  demonstrated  in  the  serum 
of  the  calf  from  the  third  to  the  fourth  day,  before  which  time  the 
blood  cells  of  guinea  pigs  were  not  dissolved. 


52  Biological,  Chemical  and  Physical  Characteristics  of  Milk. 

As  proved  by  Kraus  bacteriolytic  immune  bodies  also  pass  into 
the  milk,  in  artificially  immunized  animals,  and  into  the  body  of  the 
suckling  consuming  the  milk,  provided  the  mother  possesses  active 
immunity  (de  Blasi). 

Of  other  immune  bodies  which  are  present  in  the  blood  and 
have  been  demonstrated  also  in  the  milk  of  the  same  animal,  should 
be  mentioned  the  opsonins  (Wright),  which  influence  the  bacterins 
in  such  a  way  that  they  may  be  readily  assimilated  by  the  phago- 
cytes (Turton  and  Appleton,  Eisler  and  Sohma). 

Other  substances  which  induce  the  so-called  hypersensitive- 
ness  (anaphylaxis),  have  also  been  demonstrated  (Otto).  At 
least  it  has  been  proven  in  the  study  of  hypersensitiveness,  that 
the  off-spring  of  hypersensitized  guinea  pigs  possess  an  increased 
sensitiveness  for  homologous  antigens,  and  this  may  not  only  be 
the  result  of  the  intra-uterine  transmission  of  the  anaphylaxis 
from  the  mother  to  the  young,  but  also  of  the  transmission  of  the 
immune  bodies,  through  the  milk  of  the  mother. 

To  the  subject  of  immune  substances  belong  possibly  the  ob- 
servations made  by  Tage,  Duhat  and  Dobrowits,  during  the  treat- 
ment of  nursing  syphilitic  mothers  with  salvarsan  which  shows 
its  effect  upon  the  untreated  syphilitic  children.  Syphilitic  chil- 
dren thrive  splendidly  after  the  treatment  of  their  mother.  It 
was  impossible  to  demonstrate  arsenic  in  the  milk,  either  in  or- 
ganic or  non-organic  combination.  Ehrlich  explains  the  action 
by  the  fact  that  a  rapid  breaking  down  of  the  syphilitic  spiro- 
chaetes  in  the  mother  is  produced  through  the  action  of  the  new 
syphilitic  remedy,  and  thereby  an  elimination  of  the  endo-toxins 
is  induced.  The  antitoxins  which  develop  in  the  mothers  pass  into 
the  milk,  and  cause  a  passive  immunization  of  the  child,  through 
the  gastro-intestinal  tract ;  Jesionek,  on  the  other  hand  claims  the 
passage  of  the  arsenic  from  the  blood  of  the  treated  mother  to  the 
milk,  and  explains  thereby  the  remarkable  results  in  untreated 
children  which  are  nursed  by  the  treated  mothers. 

Very  little  is  known  with  certainty  relative  to  the  quantita- 
tive relation  which  exists  between  the  immune  bodies  appearing 
in  the  circluating  blood,  and  those  in  the  milk.  The  views  expressed 
are  too  widely  divergent.  It  is  known  of  the  anti-toxins  in  which 
this  relation  has  been  mostly  studied,  that  of  15  to  30  parts  of  the 
anti-bodies  which  are  demonstrable  in  the  blood  a  certain  amount 
appears  in  the  milk. 

These  relations  are  still  somewhat  vague,  since  the  passing 
of  the  anti-bodies  which  are  bound  to  the  albumins  and  globulins 
depends  on  the  quantitative  relation  of  these  proteids  in  the  milk, 
and  the  experimental  results  therefore  must  vary  in  accordance 
with  the  species  of  animal  used,  the  stage  of  lactation  of  the 
respective  individual,  diseases  of  the  udder,  etc. 

In  infections  of  the  udder,  for  instance  with  colon  bacilli,  anti- 


Agressins.  53 

bodies  accumulate  in  the  glands  so  that  as  a  result  the  milk  serum 
agglutinates  more  readily  than  the  blood  serum. 

Not  only  anti-toxins  and  other  protective  immune  bodies  pass 
into  the  milk,  but  substances  also  which  inhibit  the  protective 
power  of  the  body,  for  instance  aggressins,  at  least  so  long  as  the 
body  has  not  formed  anti-aggressins.  The  aggressins  for  instance 
act  against  the  dissolving  of  bacteria.  Schenk  demonstrated  anti- 
staphylolysins  and  anti-vibriolysins  in  the  milk  of  goats,  cows  and 
women. 

Otherwise  the  passage  of  toxic  substances  of  the  character 
of  antigen,  which  are  closely  allied  to  proteids,  could  be  just  as 
plausible  as  the  passage  of  the  constituents  of  the  blood  which  are 
indispensable  in  the  composition  of  the  milk.  The  passage  of 
toxins  into  the  milk  has  not  yet  been  satisfactorily  proven  for  all 
toxins. 

A  large  number  of  known  substances  from  animal  and  plant 
life  are  known  as  toxins,  that  is,  bodies  which  do  not  act  like 
chemical  poisons,  but  exert  their  toxic  action  only  after  a  period 
of  incubation,  in  which  time  fixation  takes  place. 

These  toxins  do  not  affect  all  animals  in  a  similar  degree, 
but  only  those  which  are  susceptible.  Certain  species  of  animals 
are  not  susceptible  to  certain  toxins ;  they  are  immune.  This  im- 
munity may  also  be  artifically  established  in  susceptible  animals. 
The  toxin  is  an  antigen,  and  under  certain  conditions  it  produces 
an  anti-toxin  contrary  to  the  toxins  which  act  purely  chemically. 

Among  toxins  acting  in  this  manner  may  be  mentioned  the 
products  of  metabolism  of  the  Bacillus  diphtheria,  the  Bacillus 
tetani,  the  bacillus  of  certain  forms  of  meat  poisoning — the 
Bacillus  botulinus  and  the  Bacillus  pyocyaneus,  the  bacillus  of 
blackleg,  and  the  body  substances  of  certain  bacteria  (endo-toxins). 
They  may  be  of  animal  origin :  snake  toxins,  spider  toxins,  scor- 
pion toxins,  turtle  toxins,  toxin  of  the  blood  of  eels,  salamander 
toxins,  wasp  toxins,  or  of  plant  origin,  such  as  the  abrin,  robin, 
krotin,  ricin,  etc. 

If  it  is  considered  that  the  gastro-intestinal  tract  of  very 
young  individuals  is  readily  penetrable  for  proteids,  although  pro- 
teids of  unlike  origin  pass  with  greater  difficulty  than  those  of  like 
origin,  the  question  as  to  whether  the  milk  of  the  mother  may  con- 
tain toxins  when  toxins  are  circulating  in  her  blood,  assumes  prac- 
tical importance.  This  becomes,  however,  unimportant  when  it  is 
considered  that  even  in  severely  affected  individuals  only  very 
small  quantities  of  toxins  are  circulating  free  in  the  blood.  Should 
a  part  of  these  minute  amounts  be  secreted  in  the  milk,  this  quan- 
tity itself  is  of  only  little  practical  importance  even  when  the  great 
susceptibility  of  the  intestines  of  the  suckling  is  considered. 

It  is  true  that  Miessner  succeeded  in  proving  that  mice  die 
from  tetanus  when  they  are  fed  with  raw  milk  from  a  cow  affected 
with  tetanus,  whereas  the  feeding  of  meat  has  no  influence  on  the 


54  Biological,  Chemical  and  Physical  Characteristics  of  Milk. 

health  of  the  animal;  this  proves  the  passage  of  the  tetanus  toxin 
into  the  milk. 

Older  animals  do  not  become  affected  even  after  the  adminis- 
tration per  os  of  large  doses  of  toxins,  at  least  not  from  diphtheria 
or  tetanus  toxins,  and  the  Bacillus  botulinus,  the  toxins  of  which 
are  absorbed  by  the  stomach  but  the  bacillus  does  not  thrive  in  the 
body;  therefore  the  possibility  of  secreting  these  toxins  through 
the  milk  gland  is  from  the  first  of  small  importance,  especially 
since  in  severely  affected  animals  the  secretion  ceases. 

From  a  practical  consideration  of  the  question  of  toxin  elimi- 
nation, the  plant  toxins  come  principally  into  consideration,  espe- 
cially ricin,  as  food  adulterations  to  a  great  extent  take  place  with 
ricinus  seed  and  its  flower.  An  elimination  of  ricin  with  the  milk, 
however,  has  not  been  observed  up  to  the  present  time.  Ehrlich 
was  unable  to  observe  an  elimination  of  ricin  in  mice  which  were 
under  the  action  of  ricin;  the  offspring  of  these  mice  wrere  not 
actively  immunized  against  ricin  but  acquired  only  a  passive  im- 
munity of  short  duration. 

Of  more  importance  however  are  the  bacterial  toxins,  and 
products  of  decomposition  acting  like  toxins,  which  subsequently 
develop  in  the  milk  after  certain  fermentation  processes. 

The  above-mentioned  immune  substances  are  probably  of  great 
importance  for  the  nourishment  of  the  young  and  the  sucklings. 
The  passage  of  genuine  proteids  in  very  young  individuals  with 
injured  mucous  membranes,  is  an  established  fact,  and  with  the 
globulins  anti-bodies  also  pass  into  the  blood  of  the  young,  while 
in  older  individuals  the  relatively  labile  anti-bodies  are  changed  or 
destroyed  by  the  splitting  up  of  the  proteids. 

The  absorption  of  anti-toxins  through  the  intestines  of  the 
young  has  been  proved  by  the  classical  experiments  on  sucklings 
by  Ehrlich. 

Other  works  by  Brieger,  Ehrlich,  Salge  and  Eomer  prove  that 
certain  immune  substances  of  milk  of  like  origin  pass  through  the 
intestines,  while  in  feeding  sera  or  anti-substances  of  like  origin 
contained  in  milk  of  unlike  origin  the  quantity  passed  was  only 
very  slight.  Thus  Rb'mer  succeeded  in  demonstrating  passive 
immunity  in  foals  after  feeding  them  with  anti-toxin  milk  of  like 
origin,  but  was  unsuccessful  after  feeding  anti-toxic  sera  of  like 
origin. 

^  In  calves  of  course  the  results  were  positive  even  when  the 
anti-toxin  was  mixed  with  the  milk  as  a  serum  of  unlike  origin,  but 
the  quantity  of  immune  bodies  of  unlike  origin  absorbed  was 
smaller  than  that  of  like  origin.  The  absorption  diminishes  with 
the  increase  of  the  age  of  the  animal. 

Relative  to  the  passage  of  other  immune  substances  from 
the  milk  into  the  blood  of  the  suckling,  the  same  experiences  hold 
as  a  rule  as  in  the  case  of  milk  containing  anti-toxin. 

Milk  is  not  only  a  carrier  of  anti-bodies,  and  possibly  of  anti- 


Arule  purulent  fibrinous  mastitis.     Dilation  of  the  blood  vessels    (c)  ;   with  exudate  of 
numerous  cells  into  the  alveoli  and  excretory  duct.      Hematoxylin — Sudan  III. 


Concrement    formation  in   milk  stasis  (a),  and  in  mastitis  (b)  ;  inactive   portion   of   the 

gland  (c). 

Ernst,  Milk  Hygiene. 


Precipitin.  55 

gen,  but  as  a  proteid-containing  material  it  is  an  antigen  in  itself, 
or  rather  a  collection  of  antigens,  which  may  again  produce  anti- 
bodies in  the  body  of  an  animal.  These  anti-bodies  against  milk 
not  only  develop  in  artificial  administration  by  injections,  but  also 
under  certain  conditions  during  the  natural  ingestion  of  the  milk 
per  os  as  a  food.  Although  usually  such  anti-bodies  against  nutri- 
tive proteids  of  unlike  origin  appear  only  in  intensive  over-feeding 
of  proteids  (Ascoli,  Michaelis  and  Oppenheimer,  Uhlenhuth,  and 
others),  nevertheless  in  the  presence  of  an  injured  intestinal 
mucous  membrane  the  absorption  of  proteids  of  unlike  origin  may, 
under  natural  conditions,  take  place,  and  thereby  induce  the  for- 
mation of  anti-substances. 

Moro  succeeded  in  finding  cow  milk  precipitin  in  two  instances, 
and  milk  proteid  in  one  instance  in  an  examination  of  22  anemic 
bottle-fed  children. 

Bauer  found  precipitating  substances  of  cow's  milk  in  the 
blood  of  an  emaciated  man. 

Kentzler,  with  the  aid  of  the  precipitation  test,  demonstrated 
milk  proteids  in  the  blood  of  six  human  subjects  in  which  the  gas- 
tric secretion  was  disturbed,  out  of  61  cases  that  he  examined  two 
to  three  hours  after  feeding. 

Although  milk  is  absorbed  through  the  intestines  of  older 
individuals  only  after  the  splitting  up  of  the  proteids,  nevertheless 
in  case  of  an  injured  mucous  membrane,  or  in  greatly  emaciated 
and  in  very  young  individuals  the  direct  absorption  of  unchanged 
proteids  is  possible.  Ganghofner  and  Langer  succeeded  in  proving 
this  on  very  young  rabbits,  on  pigs  and  on  newly  born  cats,  and 
they  succeeded  also  in  demonstrating  a  precipitin  formation  in  the 
blood.  Schkarin  describes  similar  results  after  the  feeding  of 
cow's  milk  to  young  rabbits. 

Lactoserum. 

It  will  be  advisable  and  appropriate  to  include  at  this  place 
a  subject  which  as  a  matter  of  fact  belongs  to  the  chapter  dealing 
with  the  characteristics  of  the  milk  of  various  species  of  animals. 
Milk  is  an  antigen  and  contains  various  antigens.  After  injecting 
the  milk  of  species  A  into  an  individual  of  species  B,  the  formation 
of  various  anti-bodies,  precipitins,  amboceptors,  etc.,  may  be  ob- 
served in  the  blood  serum  of  the  treated  individual,  which  gives 
to  the  blood  serum  the  specific  characteristics  of  lactoserum.  This 
specific  characteristic  is  shown  by  the  fact  that  the  cow  lacto- 
serum of  rabbits  produces  a  precipitation  only  when  cow's  milk 
is  used  for  the  precipitation,  but  not  with  milk  of  women  or  goats. 
Works  of  Bordet,  Fish,  Morgenroth,  Wassermann  and  Schiitze 
show  the  specific  action  of  lactosera.  With  the  aid  of  such  sera 
the  possibility  is  afforded  of  differentiating  the  milk  from  various 
species  of  animals. 


~)Q  Biological,  Chemical  and  Physical  Characteristics  of  Milk. 

This  however  does  not  end  the  degree  of  the  specificity,  as  it  is  possible  with  the  aid 
of  the  precipitation  method  to  differentiate  various  kinds  of  proteids  of  one  and  the 
same  milk.  If  the  soluble  proteid  bodies  are  separated  from  the  undissolved  casein  by 
filtration  (Schlossmann),  then  the  rabbits  which  are  treated  with  soluble  proteid  bodies 
furnish  sera  which  react  only  to  milk  albumin  and  globulin  (Hamburger). 

It  is  of  further  interest  that  cow-casein  sera  gave  precipitation 
with  cattle  blood  (Hamburger),  the  same  as  is  the  case  with  lac- 
tosera  (Landsteiner,  Halban,  Dungern,  F.  Meyer,  L.  Aschoff). 

Moreover  lactosera  immobilizes  spermatozoa  of  bulls,  and 
dissolves  red  blood  corpuscles  of  cattle.  However  no  reaction 
results  from  the  addition  of  cattle  blood  serum  containing  anti- 
bodies to  cow  milk  (Meyer).  The  anti-serum  sensitized  against 
cattle  blood  only  gives  slight  precipitation  when  it  possesses  espe- 
cially high  value  (Uhlenhuth  and  Sclmtze).  The  same  conditions 
were  found  in  preparations  of  human  blood,  and  women's  milk,  by 
Halban  and  Landsteiner. 

Uhlenhuth  and  Sclmtze  proved  that  the  differentiation  of 
various  kinds  of  milk  shows  that  the  biological  method  succeeds 
even  when  the  milk  is  heated  to  a  high  temperature  (114  deg.  C.  in 
an  autoclave) ;  if  the  milk  antigen  was  heated  20  minutes  at  120 
deg.  C.,  lactosera  resulted,  which  only  contained  coagulins,  but  no 
hemolysins.  Sion  and  Laptes  showed  that  the  most  varied  splitting 
and  decomposing  changes  of  cheese-making  and  cheese-ripening 
do  not  influence  the  antigen  to  such  an  extent  that  the  kind  of  milk 
used  in  making  the  cheese  could  not  be  determined  by  the  biological 
method.  This  specificity  is  of  course  manifested  even  in  the  use 
of  lactosera,  but  is  not  absolute,  only  relative.  Lactosera  also  gave 
a  reaction  with  the  milk  of  closely  related  animals,  the  same  as 
has  been  established  for  blood  sera,  meat  sera,  etc.  Thus  for  in- 
stance it  is  impossible  to  differentiate  sheep's  milk  from  goat's 
milk  (Uhlenhuth,  Moro,  Gengou),  although  it  is  possible  to  draw 
conclusions  from  the  comparison  of  the  intensity  of  the  reaction 
in  the  homologous  milk. 

Other  authors,  as  for  instance  Bauer,  succeeded  in  demonstrat- 
ing by  the  so-called  complement-fixation  method,  the  presence  of 
cow's  milk  in  woman's  milk,  even  when  only  1  c.  c.  of  the  former 
had  been  added  to  1000  c.  c.  of  the  latter. 

If  specific  serum  which  has  been  heated  for  a  half  hour  at  57 
deg.  C.  is  mixed  with  milk  and  as  much  complement  is  added  as 
is  necessary  for  the  dissolving  of  the  subsequently  added  blood 
corpuscle  suspension,  with  the  aid  of  certain  quantities  of  hemo- 
lytic  amboceptors,  then  the  amboceptors  of  the  lactoserum  bind  the 
complement,  provided  they  find  in  the  milk  the  specific  antigen 
(cow  lacto serum-cow  milk),  and  the  subsequently  added  hemolytic 
system,  free  of  complement,  no  longer  finds  complement,  so  hemo- 
lysis  does  not  occur,  but  instead  fixation  of  complement  results.  If 
there  is  no  specific  antigen  present  (if  the  milk  to  be  examined  con- 
tains no  cow  milk),  the  complement  remains  free  to  be  utilized 
later  by  the  hemolytic  amboceptors  and  the  blood  cells,  for  the 


Anopliylaxia.  57 

functionating  liemolytic  system,  and  a  solution  of  the  blood — liemo- 
lysis — results. 

The  appearance  of  "anaphylaxia"  may  also  be  produced  ex- 
perimentally with  milk  (Arthus  and  Besredka).  It  may  be  brought 
on  by  raw  as  well  as  by  boiled  milk. 

The  phenomenon  of  hypersensitiveness  as  is  known,  results  when  a  proteid  of  un- 
like origin  is  injected  into  an  animal  and  later  after  a  period  of  time  the  same  proteid 
is  re-injected.  At  the  second  injection  (or  only  after  later  ones,  depending  on  the  ex- 
perimental animal  and  the  quantity  of  proteid),  the  experimental  animal  reacts  violently 
with  indications  of  extreme  sickness  (Von  Behring,  Eichet  and  Arthus),  which  may  even 
result  in  death  from  convulsions  and  pulmonary  edema. 

Miessner  succeeded  in  producing  a  hypersensitiveness  against 
homologous  kinds  of  milk  in  guinea  pigs,  sometimes  after  one  in- 
jection, but  more  markedly  after  repeated  subcutaneous  injec- 
tions, and  with  the  greatest  certainty  after  intra-abdominal  in- 
jections of  small  quantities  of  raw  milk.  The  best  reaction  was 
obtained  in  the  animals  after  three  intra-abdominal  injections 
of  .  5  c.  c.  of  milk,  on  three  successive  days.  After  the  preparation 
of  the  animal  40  to  50  days  should  elapse  before  the  test  which  is 
made  by  intra-cardial  injections. 

After  repeated  injections  it  is  possible  to  demonstrate  an  ana- 
phylaxis  in  most  cases  even  with  boiled  milk. 

In  order  to  utilize  the  biological  test  for  milk  differentiation 
several  rabbits  should  be  prepared.  This  is  carried  out  by  in- 
travenous injections  of  small  quantities  (5  or  more  c.  c.)  of  milk 
heated  for  a  long  time  to  65  deg.  C.  The  injection  is  repeated  5 
to  8  times  at  intervals  of  1  to  4  days.  In  from  14  to  20  days  after 
the  last  injection  the  lactoserum  may  be  tested  for  its  effectiveness 
and  if  found  suitable,  may  then  be  drawn.  For  this  purpose  the 
animal  is  kept  without  food  for  one-half  day,  (in  order  not  to 
obtain  a  cloudy  serum),  a  venous  hyperemia  of  the  ear  is  produced 
by  intensive  lighting  of  the  ear  with  the  aid  of  an  electric  globe,  or 
by  rubbing  it  with  xylol,  and  the  vein  is  then  punctured  with  a 
fine  hypodermic  needle.  Several  cubic  centimeters  of  blood  are 
drawn,  which  is  allowed  to  coagulate;  the  blood  clot  is  separated 
and  allowed  to  stand  for  24  hours  in  an  ice  chest.  The  test  is  made 
as  follows: 

1.  Establish  the  dilutions  of  the  serum  which  are  capable 
of  producing  a  visible  precipitation  in  3  c.  c.  of  milk  dilution,  with 
1 :60  physiological  salt  solution,  or 

2.  Establish  the  dilution  of  milk  with  1 :10  physiological  salt 
solution,  in  which  when  mixed  in  the  relation  of  1:6,  the  lacto- 
serum still  produces  a  precipitation. 

The  most  active  lactoserum  is  the  best  adapted  for  use. 

The  rabbit  is  bled  to  death  (slight  anesthesia-opening  of  the 
thorax-puncturing  of  the  heart),  the  blood  for  the  collection  of  the 
serum  is  allowed  to  stand,  the  serum  is  drawn  off  in  quantities  of 
2  to  5  c.  c.  into  small  vials,  and  placed  in  an  ice  box  for  safekeeping. 


CHAPTER  V. 

PROCUREMENT  OF  COW'S  MILK. 

As  has  already  been  mentioned  milk  secretion  may  be  retained 
for  a  long  time  by  proper  emptying  of  the  gland  and  by  the  stimu- 
lation exerted  on  the  gland  in  the  process  of  emptying.  In  the 
presence  of  incomplete  milking,  in  over-extending  the  time  of 
milking,  and  in  stasis  of  the  milk,  a  condition  of  the  gland  results, 
which  finally  passes  into  a  state  of  inactivity,  when  the  stimulating 
condition  which  is  exerted  by  the  retention  of  the  secretion  on  the 
secreting  epithelia  does  not  again  appear  with  the  act  of  a  com- 
plete milking.  The  milk  secretion  therefore  is  largely  dependent 
on  the  activity  which  is  exerted  on  the  gland  from  the  outside,  such 
as  the  sucking  act  of  the  calf,  or  artificial  milking. 

Artificial  emptying  is  carried  out  in  various  ways: 

1.  By  closing  the  upper  portion  of  the  teat  with  the  aid  of  the 
thumb  and  index  finger,  and  pressing  out  the  contents  of  the  cis- 
tern by  gradual  closing  of  the  hand  to  a  fist  in  such  a  way  that  first 
the  middle  finger,  then  the  ring  finger,  and  finally  the  small  finger 
presses  the  milk  downward  and  from  the  opening  of  the  teat.    The 
open  hand  is  passed  up  again,  forcing  the  milk  into  the  cistern  from 
the  upper  part  of  the  quarter,  the  thumb  and  index  finger  again 
squeeze  the  cistern  at  its  base,  and  the  procedure  ends  as  before. 
This  manipulation  is  known  as  "fisting"  or  full  handed  milking. 

2.  By  stroking  with  the  closed  thumb  and  index  finger  from 
the  base  of  the  teat  to  its  point  the  milk  may  also  be  pressed  out 
("stripping"  or  "tipping").     This  method  of  milking  requires 
much  less  strength  than  the  full  handed  milking,  but  causes  a 
lengthening  of  the  teats,  and  is  a  painful  operation  for  the  animal, 
as  it  is  frequently  accompanied  by  injuries  to  the  tissue,  and  tear- 
ing of  the  mucous  membrane. 

The  full  handed  milking  may  be  carried  out  by  dry  milking, 
while  "stripping"  succeeds  only  when  the  teat  and  hand  are 
moistened  (moist  milking),  since  the  necessary  smoothness  and 
slipperiness  of  the  skin  result  only  from  moistening. 

If  the  teat  is  not  pressed  with  the  extended  thumb  (a  brace 
for  the  index  finger),  but  the  thumb  is  crooked  and  the  teat  is 
pressed  and  stringed  with  the  bent  index  finger  against  the  nail 
surface  of  the  thumb  and  the  knuckle  of  the  joint,  this  is  spoken  of 

58 


Methods  of  Milking.  59 


as  " streak  milking"  or  stripping  with  bent  thumb.  The  "streak 
milking"  may  be  completed  by  stripping  or  by  full  handed  milking. 
Full  handed  milking  and  this  method  combined  with  ' '  streak  milk- 
ing" are  according  to  Henkel  permissible;  the  other  kind  of 
milking  should  be  prohibited  since  the  teats  are  too  much  extended. 

The  udder  should  be  milked  by  the  dry  method  since  this 
method  of  milking  is  more  cleanly  than  moist  milking,  in  which  the 
fingers  become  moistened  by  the  milk,  and  although  they  slip 
easily,  at  the  same  time  they  wash  off  the  dirt  from  the  entire  teat. 

It  is  to  be  regretted  that  moist  milking  and  stripping  because 
of  their  labor  saving  advantages,  are  preferred  by  many  milkers 
on  account  of  their  convenience,  and  even  if  they  are  urged  to 
carry  out  the  ordinary  dry  milking,  as  soon  as  they  are  left  with- 
out supervision  they  will  at  once  fall  into  the  same  fault. 

The  order  of  milking  the  various  teats  differs.  Milking  from 
the  same  side  is  supposed  to  induce  the  development  of  the  side 
first  milked,  since  the  half  of  the  udder  first  milked  is  worked  with 
fresh  strength  while  the  subsequently  milked  quarters  are  not 
emptied  as  well  on  account  of  the  beginning  weariness  of  the 
milker  and  therefore  they  develop  less  perfectly.  The  hind  quar- 
ters are  either  not  emptied  entirely  when  the  milkers  have  com- 
pleted the  milking  of  the  fore  quarters,  or  else  one  hand  of  the 
milker  rests  while  he  finishes  milking  the  hind  quarter  with  the 
other.  The  same  applies  in  milking  the  teats  crosswise,  when  the 
hind  quarter  of  one  side  of  the  udder  is  milked  at  the  same  time  as 
the  fore  quarter  of  the  other  side.  Therefore  it  is  advisable  to  milk 
the  fore  quarters  together  and  the  hind  quarters  together,  and  the 
milking  should  be  undertaken  first  on  those  quarters  which  appear 
to  be  most  distended. 

With  the  drawing  of  the  milk  from  the  udder  through  milking 
the  teats,  the  complete  act  of  milking  is  not  concluded,  as  the  udder 
has  not  yet  been  sufficiently  exhausted  in  its  production.  The  cause 
of  this  may  lie  in  the  fact  that  the  milk  cannot  be  emptied 
by  the  simple  sucking  action  from  the  smallest  milk  ducts  and 
alveoli,  or  that  after  the  apparent  entire  emptying,  the  milk  pro- 
duction still  goes  on  if  the  gland  cells  are  properly  stimulated  in 
their  functions. 

As  the  flowing  in  of  milk  may  be  accomplished  through  the 
so-called  "preparation,"  that  is  stroking  or  massage  of  the  bases 
of  the  teats  and  quarters,  the  same  result  is  possible  through  the 
so-called  "clean  milking,"  or  "after  milking,"  to  obtain  an  addi- 
tional quantity,  which  is  especially  rich  in  fat. 

These  methods  vary  and  are  practiced  in  different  ways  in  dif- 
ferent localities. 

The  best  known  method  of  "clean  milking,"  and  one  which 
has  been  mostly  studied,  is  that  practiced  by  Hegelund,  a  Danish 
veterinarian.  This  method  is  divided  into  the  following  phases : 


Procurement  of  Cow  's  Milk. 


1.  Milking  through  simultaneous  full  handed  milking,  first  of 
the  fore  and  then  of  the  hind  teats,  until  the  milk  flows  no  longer. 

2.  This  milking  is  followed  by  the  "  clean  milking,"  which 
consists  in  massaging  the  udder,  beginning  at  the  teat  up  to  the 
base  of  the  teat,  and  as  high  as  possible  extending  on  to  the  paren- 
chyma.   While  the  first  act  corresponds  with  the  usual  full  handed 
milking,  the  second  act  massages  with  a  milking  motion,  the  base 
of  the  cistern,  and  the  third  is  carried  out  by  surrounding  between 
the  thumb  and  the  hand,  and  stroking  down  the  lower  part  of  the 
quarter,  that  is,  through  simultaneous  pressing  against  each  other 
of  both  quarters  of  opposing  sides. 

3.  The  first  manipulation  of  the  after  milking  is  carried  out 
by  pressing  the  right  quarters  of  the  udder  against  each  other,  the 
left  hand  being  placed  on  the  hind  quarter  and  the  right  hand 
on  the  fore  quarter.    In  case  of  a  large  udder,  only  one  quarter 
is  grasped  at  one  time.    The  hands  are  then  pressed  upwards  with 
a  rubbing  motion  on  the  gland  which  exerts  a  massage  on  the  par- 
enchyma of  the  udder,  this  being  repeated  three  times,  followed  by 
milking  out  the  cistern.     This  manipulation  is  repeated  until  no 
more  milk  is  obtained,  when  the  left  quarters  are  treated  in  a 
similar  manner. 

In  the  second  manipulation  the  fore  quarters  are  milked  by 
placing  one  hand  on  the  outside  of  the  quarter  and  the  other  in 
the  division  between  the  two  fore  quarters.  The  hands  are  pressed 
against  each  other  followed  by  milking  of  the  teats.  Then  the 
hind  quarters  are  milked  by  placing  a  hand  on  the  outside  of  each 
quarter  in  such  a  way  that  the  fingers  are  turned  upwards  and  the 
thumb  placed  in  front  of  the  hind  quarter.  The  hands  grasp  the 
quarter  and  are  pressed  upward;  then  they  are  lowered  and  the 
milking  follows.  This  is  also  repeated  until  no  more  milk  is 
obtained. 

In  the  third  manipulation  the  milker  imitates  the  butting  mo- 
tions of  a  calf  during  sucking.  The  hands  loosely  surround  the 
teats  and  the  quarters  are  lifted  and  pushed  against  the  abdominal 
wall  so  that  the  gland  tissue  is  shaken.  This  lifting  and  pushing 
motion  is  repeated  three  times  and  the  teats  are  then  milked 
out.  Following  this  procedure  on  the  fore  quarters  the  hind 
quarters  are  treated  in  a  like  manner,  until  no  more  milk  is  ob- 
tained. 

The  works  of  Aashamar,  Alfonsus,  Woll,  van  der  Zande  and 
Henkel,  and  Wenk,  speak  of  the  excellence  of  the  method  of 
Hegelund. 

According  to  Henkel  the  increase  of  the  milk  yield  in  37 
Simmenthal  cows  was  217.4  gm.  (3.4%)  per  milking  on  an  aver- 
age. Wenk  succeeded  in  obtaining  from  24  cows  4.5  kg.  of  milk 
per  day  more  than  with  the  ordinary  method  of  milking. 

Of  course  against  the  increase  of  yield  must  be  placed  the 


Methods  of  Milking.  61 


additional  work  and  time,  which  is  an  additional  expense  and 
considerably  diminishes  the  profit  derived  from  the  increased  yield 
of  milk,  and  may  even  nullify  it,  since  it  involves  the  employment 
of  additional  help.  The  principal  advantages  of  Hegelund's  meth- 
od lie  in  the  fact  that  the  milkers  are  held  down  to  thorough  work, 
and  the  milk  glands  are  subjected  to  more  correct  and  appropriate 
handling. 

A  modified  form  of  Hegelund's  method  is  the  so-called  "New 
Algauer  milking  method, ' '  which  combines  the  acts  of  the  Algauer 
method  with  those  of  Hegelund.  The  massage  of  each  quarter 
is  carried  out  with  both  hands.  The  method  of  Sondergaard  aims 
to  simplify  the  time-consuming  work  of  "clean  milking"  inasmuch 
as  the  residual  milk  is  obtained  by  a  wide  extensive  hold  of  the 
halves  of  the  udder  at  their  bases,  and  pressing  at  the  same  time 
and  stroking  downwards.  The  principal  factor  in  each  method 
of  milking  is  that  the  udder  should  be  thoroughly  emptied,  and 
this  can  only  take  place  when  each  part  of  the  milk  gland  is  stimu- 
lated by  massage  to  the  limit  of  its  production. 


CHAPTER  VI. 

INTERNAL  INFLUENCES  ON  THE  CHARACTER 

OF  MILK. 

The  influences  which  must  be  considered  in  the  formation  of 
milk  may  be  separated  into  internal  influences  which  lie  in  the 
individual  characteristics  and  in  the  immediate  condition  of  health 
of  the  animal,  and  in  outside  influences,  such  as  stabling,  feeding, 
*"etc.,  which  again  act  only  in  that  they  influence  the  internal 
condition. 

As  internal  influences  may  be  considered  the  characteristics 
of  the  breeds,  strains,  family,  individual,  age,  influences  of  the 
lactation  period,  pregnancy,  and  the  general  and  local  conditions 
of  health.  The  outside  influences  may  be  considered  under  care 
and  attendance,  feed,  medical  treatment,  climatic  influences,  meth- 
ods of  milking,  etc. 

Following  this  outline  the  internal  influences  on  the  formation 
of  milk  will  be  considered  first. 

Breed,  Family,  Heredity,  Individual  Characteristics. 

Age,  Lactation  and  Other  Special  Conditions 
of  the  Individuals. 

The  influence  of  the  breed  on  milk  formation  is  generally 
known.  There  are  beef  breeds  which  fatten  especially  well,  milk 
breeds  in  which  milk  production  is  especially  prominent,  and 
breeds  which  possess  the  ability  to  produce  both  milk  and  meat. 

Breeds  of  low  lands  and  their  crosses  produce  more  milk 
with  lower  percentage  of  fat  than  breeds  from  the  highlands.  Ac- 
cording to  the  quantity  of  milk  produced,  the  breeds  are  headed 
by  the  Holsteins,  Angler,  Oldenburger,  East  Friesian,  Breiten- 
burger,  Wilstermarscher,  Dithmarscher  with  20  to  25  liters  of  milk 
per  day  per  animal  at  the  height  of  production,  with  percentages  of 
fat  from  2.5  to  3  to  3.4.  Smaller  quantities  of  milk  are  given  by 
the  grayish-brown  mountain  cattle,  the  Swiss  and  Algauer,  with 
3.6  to  3.7%  of  fat,  and  the  spotted  mountain  cattle,  for  instance 
Simmenthal,  Misbacher  and  Pinzgauer,  with  3 . 5  to  4%  of  fat.  The 
fat  content  of  the  Westerwalder  and  of  the  Schlesian  red  cattle 

62 


Influence  of  the  Breed.  53 


varies  between  3.5  to  3.6%,  while  the  English  Shorthorns  and 
Ayrshires  give  3.7  and  3.8% ;  the  richest  in  fat  is  the  milk  of  the 
Vogelsberger  and  Harz  cattle  (3.9  to  4.2%)  and  that  of  the  Jer- 
sey with  5  to  5.4%  (Ramm).  Reference  should  be  made  here  to 
the  following  results  of  tests  of  production  made  with  Simmenthal, 
Vogelsberger,  Westerwaldern  and  Lahn  breeds  of  cows. 

Simmenthal  Lahn  Vogelsberg  Westerwald 
Average  weight  of  the 

tested  animals 578*  502  427  395          kg 

Average   production    2495  2650  1919  1878 

Fat  contents 4.001%  4.001%  3.74%  4.1% 

Individual  maximum  production  ....      4562  3955  3800  3234          kg 

For  100  kg.  body  weight 431.1  528  450  477.4        " 

*The  cow  with  maximal  production  stood  last  year  in  ninth  place.  17  cows  pro- 
duced over  3000  kg.  each. 

The  fluctuation  is  not  in  fat  content  alone,  but  also  in  the 
other  solid  substances.  Milk  which  is  rich  in  fat  as  a  rule  contains 
more  of  the  other  solid  constituents  as  well.  The  proportion  of 
individual  factors  of  the  dry  substances  is  variable ;  in  cattle  from 
the  highlands  for  instance,  the  casein  was  76.24%  of  the  dry  sub- 
stance, in  cattle  of  the  lowlands  it  averaged  73.78%  (Fischer). 

Fat  from  the  milk  of  the  mountain  breeds  is  generally  under  otherwise  similar  con- 
ditions, the  richest  in  fatty  acid  of  molecular  weight;  the  fat  globules  of  the  breeds  of  the 
lowlands  are  smaller  than  the  fat  globules  of  the  cattle  from  the  highlands.  Babcock 
mentions  that  Jersey  and  Guernsey  cows  produce  larger  and  more  uniform  fat  globules 
than  the  Holsteins,  while  Ayrshires  have  small,  irregular  fat  globules  in  their  milk.  Milk 
with  large  fat  globules  is  preferable  for  butter  making,  since  these  produce  butter  of 
good  consistence  and  good  taste  with  a  low  melting  point. 

The  ash  content  of  milk  from  highly  bred  animals  is  some- 
times somewhat  lower  in  CaO  and  P205  than  that  of  the  common 
breeds,  but  the  fluctuation  is  such  that  definite  deductions  cannot 
be  established.  In  highly  improved  breeds  Pages  found:  CaO  in 
0.143  to  0.227%  and  P265  in  0.18  to  0.273%;  in  common  breeds 
the  same  elements  amount  to  0.15  to  0.204,  and  0.153  to  0.296, 
respectively. 

These  characteristics  of  breeds  are  general,  but  they  are  not 
so  constant  that  individual  strains,  individual  families,  and  espe- 
cially particular  animals  may  not  present  exceptions.  This  fact 
forms  the  basis  of  breeding  for  increased  milk  production  within 
individual  breeds. 

Good  milk  cows  should  be  bred  to  bulls,  whose  mothers  and  sisters  were  or  are 
known  to  be  good  milkers,  and  then  it  may  be  expected  that  the  good  characteristics 
of  the  family  will  be  inherited.  In  experiments  extending  over  eight  years  Hogstrom 
tried  to  discover  whether  the  characteristics  of  producing  milk  of  certain  fat  contents 
could  be  transmitted  by  bulls  to  future  generations.  The  large  majority  of  female 
progeny  produced  a  higher  fat  content  than  the  milk  of  their  mothers,  which  points 
to  a  positive  influence  from  the  male  animal.  In  cases  in  which  the  fat  content  of  the 
mother  was  3.08  to  3.77%  the  fat  content  of  the  milk  of  the  daughter  increased  mate- 
rially;- but  as  soon  as  the  fat  reached  or  exceeded  3.77%,  the  influence  of  the  bull  was 
no  longer  sufficient  to  further  increase  the  percentage  of  fat,  and  the  percentage  re- 
mained lower  than  in  the  mother.  (The  experiences  of  Hogstrom 's  were  confirmed  by 
the  rule  laid  down  by  Galton.) 


54  Internal  Influences  on  the  Character  of  Milk. 

The  great  variation  which  occurs  in  the  milk  production  of 
individuals  of  the  same  breeds  depends  on  hereditary  qualities. 
According  to  the  statistics  of  the  dairy  control  station  at  Algau, 
animals  of  the  Algauer  breed  produce : 

Quantity  of     Fat  Percentage        Quantity  of 
Milk  Fat 

Maximal  production 5201  kg.         4.603         181.93  kg. 

Minimal  production  1255  kg.         2 . 493          45 . 31  kg. 


Difference  3946  kg.  2.11  136.62  kg. 

Among  50  of  the  Jeverland  breed 

Maximal  production 8699  kg.  3.713  286.76  kg. 

Minimal  production  2449  kg.  2.482  75.21  kg. 


Difference  6250  kg.        1.231        211.55  kg. 

The  production  of  single  individuals  during  the  lactation 
period  is  sometimes  remarkably  large.  Some  of  the  following 
data  relative  to  production  is  taken  from  Kirchner's  handbook. 

Percentage        Quantity 
Author  Cow  Quantity  of  Milk  of  Fat  of  Fat 

Kirsten         Wesermarsch  ..   11291         kg.         2.78         324        kg. 

5th  calving 

Kirsten         East  Friesian  . .     9047.75kg.         3.07         277.77kg. 
6th  calving 

Woll  Guernsey    6768        kg.        5.745      388.8    kg. 

"Yeksa  Sunbeam" 

Kirchner  also  quoted  a  case  in  which  a  farmer  observed  that 
a  seven-year  old  cow  in  the  second  month  after  calving  still  pro- 
duced 50  liters  of  milk  per  day. 

Just  as  the  quantity  of  milk  and  percentage  of  fat  may  vary, 
so  also  the  fat-free  solid  substances  may  vary  in  the  individuals, 
although  only  within  narrow  limits.  The  rule  also  holds  good  here 
that  an  individual  with  milk  rich  in  fat  will  at  the  same  time  pro- 
duce more  fat-free  solids. 

Normally  fed  animals  which  are  not  individually  large  pro- 
ducers cannot  be  brought  up  to  a  remarkable  increase  of  produc- 
tion through  any  agency.  The  elimination  of  the  poor  assimilators 
of  food  in  favor  of  good  producers,  which  is  a  matter  of  economic 
necessity,  should  be  based  upon  the  capacity  of  the  individual  cow 
to  properly  utilize  her  food.  Only  through  a  systematic  test  of 
milkings  and  production  records  can  the  profits  of  the  dairy  be 
increased. 

In  judging  individuals  as  milk  producers  by  their  external 
conformation,  the  following  rules  of  the  German  Society  for 
Breeds  and  Breeding  may  serve  as  a  basis : 


Influence  of  Age.  65 


(a)     Heavy  milk  production  is  usually  associated : 

1.  With  low  body  weight, 

2.  With  low  measurement  at  the  shoulder, 

3.  With  a  straight  back,  although  slight  deviations  should 
not  be  considered  as  signs  of  small  milk  productiveness. 

4.  With  more  or  less  prominent  hips  and  rump  according  to 
the  characteristics  of  the  breed. 

5.  With  the  more  pronounced  depth  of  thorax ;  heavy  milkers 
are  often  narrow  and  flat  chested ; 

6.  With  long  shoulders, 

7.  With  long  rumps, 

8.  With  long,  narrow  head, 

9.  Generally  with  fineness  of  horn, 

10.  With  fine  bony  structure ; 

11.  The  most  important  is  the  udder.     The  best  cows  have 
large  udders  of  spongy-granular  consistence,  with  large  tortuous 
mammary  veins,  large  milk  wells,  and  easily  movable  skin. 

The  skin  should  lay  together  over  the  perineal  surface  of  the 
udder  in  4  to  6  or  more  large,  well  developed  folds.  The  udder 
should  collapse  thoroughly  after  milking,  and  the  animals  should  be 
easy  milkers.  Relatively  early  calving  seems  to  have  a  good  in- 
fluence. The  possibility  of  estimating  the  qualitative  production 
of  milk  from  external  conformations  is  only  very  slight.  As  a 
rule,  as  shown  by  investigations,  the  smaller  and  shorter  animals 
with  fine  long  bones  produce  milk  of  higher  quantity,  and  above 
all  milk  with  a  large  yield  of  fat. 

The  productiveness  of  one  and  the  same  individual  varies, 
especially  with  age  and  the  lactation  period.  Cows  with  the  first 
calf,  provided  normal  conditions  prevail,  do  not  produce  as  much 
milk  as  after  subsequent  calvings ;  as  a  rule  when  cows  reach  the 
age  of  7  to  9  years  with  the  fifth  and  sixth  calf,  the  maximum  pro- 
duction is  obtained.  With  the  advance  of  age  the  production 
again  gradually  recedes.  The  proportion  of  solids  is  higher  in 
cows  with  the  first  calf  than  in  those  which  have  calved  several 
times;  the  quantity  of  fat  on  the  other  hand,  as  compared  with 
that  of  older  cows,  is  smaller  (Teichert,  Hittcher,  Hogstrom,  Vieth 
and  others). 

The  variations  which  are  manifested  in  the  production  of  milk 
during  single  lactation  periods  are  considerable,  and  depend  en- 
tirely upon  the  individual,  as  does  the  length  of  the  milking  period. 

For  a  few  days  after  parturition  a  product  is  secreted  which 
has  very  little  in  common  with  milk,  and  which  may  be  considered 
as  a  product  of  glandular  inflammation  as  a  result  of  physiological 
irritation.  It  corresponds  strikingly  in  its  appearance  and  com- 
position, as  well  as  in  the  microscopical  appearance  of  its  cream 
and  sediment  with  the  inflammatory  product  of  the  milk  gland. 

This  product  called  colostrum  is  a  yellowish  or  even  yellowish-red,  slimy  fluid, 
with  an  acid  reaction.  Corresponding  to  the  increased  content  of  albumen,  globulin  and 


55  Internal  Influences  on  the  Character  of  Milk. 


fat  in  colostrum,  as  compared  with  ripe  milk,  the  amount  of  dry  substances  in  colos- 
tral  milk  is  very  high,  and  its  specific  gravity  is  increased.  The  amount  of  urea,  cre- 
atinin,  cholesterin,  and  lecithin  in  colostrum  is  increased.  The  milk  at  this  stage  is 
rich  in  fat-containing  glandular  epithelium  in  the  form  of  foam  cells,  and  seal-ring- 
shaped  cells  with  so-called  caps  and  moons,  and  in  albuminophores.  Numerous  leuco- 
cytes are  to  be  found,  and  during  the  first  days  red  blood  corpuscles  are  also  present 
in  great  numbers.  According  to  Emmerling,  cow  colostrum,  on  the  rnorning  after  the 
birth  of  the  calf,  consists  of  76.14%  of  water,  and  23.86%  of  dry  substance,  of  which 
4.705%  is  casein,  0.58  albumen,  8.320  globulin.  Compared  with  normal  milk,  the  fat 
content  is  increased  or  diminished,  the  milk  sugar  diminished,  and  the  ash  contents 
increased. 

Engling  found  the  following  values  for  colostrum: 

Immediately  after  After  10  After  24  After  48     After  72 

calving  hours  hours  hours  hours 

Specific   gravity    1.068  1.046  1.043  1.042  1.035 

Solids   26.83  21.23  19.37  14.19  13.36 

Casein      2.65  4.28  4.5  3.25  3.33 

Albumin  and  globulin 16.56  9.32  6.25  2.31  1.03 

Fat     3.53  4.66  4.75  4.21  4.8 

Milk    sugar    3.0  1.42  2.85  3.46  4.1 

Ash      1.18  1.55  1.02  0.96  0.82 

The  composition  of  the  ash  differs  from  that  of  ripe  milk,  as  may  be  observed 
from  the  findings  of  Schrodt  and  Hansen: 

Ripe  Milk   (10  days 
Colostrum  after  calving) 

17.4  24.12 

10.10  8.72 

22.99  22.69 

6.88  2.92 

0.42  Traces 

2.82  4.10 

34.30  30.73 

6.85  8.30 

The  ferments  in  colostrum  also  deserve  special  consideration. 
The  amylase  content  is  considerably  increased,  also  the  amount 
of  catalase.  During  the  colostral  period  the  milk  further  con- 
tains hemolytic  amboceptors  and  increased  complement.  Formalin 
methylene  blue  is  not  decolorized.  The  reaction  of  the  colostrum 
is  acid. 

The  colostral  period  lasts  from  3  to  5  days  after  calving.  In 
heifers  the  transition  period  results  more  slowly  than  in  old  cows 
(Deisman,  Hittcher).  Up  to  the  end  of  this  period  there  is  a 
constantly  increasing  approach  to  the  properties  of  ripe  milkr 
together  with  an  increase  in  the  yield,  which  continues  to  increase 
until  the  first  or  second  month,  and  then  gradually  recedes  and 
finally  rapidly  diminishes  towards  the  end  of  the  lactation  period. 
The  reduction  of  the  milk  yield  corresponds  with  an  increase  in 
the  percentage  of  fat.  The  fat  globules  become  smaller  and  more 
numerous.  At  the  end  of  the  lactation  period  the  milk  again 
assumes  the  character  of  colostrum,  becoming  especially  rich  in 
chlorine,  and  sodium  oxide,  while  the  phosphoric  acid  and  the 
potassium  contents  appear  diminished.  The  milk  becomes  salty, 
bitter,  and  its  reaction  alkaline.  The  entire  time  of  lactation  or 
one  lactation  period,  usually  lies  between  the  birth  of  two  calves, 


Influence  of  Disease.  67 

and  is  divided  into  the  lactation  period  and  the  dry  period.  Good 
milk  cows  give  milk  on  an  average  for  300  days.  Cows  which  are 
not  bred  again,  or  which  cannot  be  impregnated,  may  have  a  con- 
siderably longer  lactation  period. 

During  estrum  a  considerable  diminution  of  milk  in  quantity 
and  quality  may  be  observed  in  cows.  Sucking  calves  may  at  this 
time  become  affected  with  digestive  disturbances.  Hittcher  and 
Neumann  state  that  the  quantity  and  the  proportion  of  fat  dimin- 
ish, while  the  casein  contents  and  the  specific  gravity  of  the  milk 
are  increased.  There  are  however  no  set  influences  in  one  and  the 
same  animal,  and  still  less  so  in  different  individuals.  Sometimes 
the  quantity  of  milk  even  increases,  and  not  infrequently  the  milk 
becomes  abnormally  rich  in  fat  (Martiny).  Fascetti  and  Bertozzi 
found  diminished  quantity,  increased  specific  gravity,  and  in- 
creased dry  substance,  which  they  supposed  resulted  from  the  in- 
creased proteid  contents,  especially  from  the  increase  of  fat.  The 
volatile  fatty  acids  in  the  fat  according  to  Nilsen  are  diminished, 
and  the  degree  of  acidity  of  the  milk  is  frequently  increased  (Mez- 
ger).  As  a  whole,  however,  the  milk  is  not  materially  changed 
(Weber). 

No  observations  have  been  made  on  the  influence  of  coition 
and  the  beginning  of  another  pregnancy.  However  the  milk  of 
cows  far  advanced  in  pregnancy  frequently  has  a  lower  value.  It 
coagulates  sometimes  as  early  as  in  the  sixth,  seventh,  or  eighth 
month  of  the  gestation  period.  Finally  it  becomes  slimy,  yellow, 
and  shortly  before  the  cow  goes  dry  it  shows  a  similarity  to  colos- 
trum. The  amount  of  phosphoric  acid  and  lime,  contrary  to  that 
in  colostrum  immediately  after  calving,  is  diminished,  and  the 
taste  is  bitter  and  rancid  (Backhaus). 

If  cows  are  spayed  5  to  6  weeks  after  calving  the  milk  is 
supposed  to  be  richer  in  fat,  casein,  and  ash.  The  lactation  period 
of  such  cows  is  considerably  lengthened,  according  to  Gouin  ex- 
tending to  6  years.  Lajoux  on  the  other  hand  states  that  in  healthy 
animals  the  quality  of  the  milk  remains  the  same,  but  during  the 
course  of  lactation  the  cows  do  not  dry  off  so  rapidly  and  the  yield 
is  therefore  greater. 

Milk  which  is  produced  after  abortion  is  supposed  to  be  sim- 
ilar to  that  of  ripe  milk  (Schaffer  and  Hess).  The  lactation  period 
however  is  short,  and  the  milk  yield  small. 

If  the  cow  remains  farrow  for  a  long  time  a  greater  yield  is 
obtained.  This  however  is  only  slight,  and  does  not  compensate  for 
the  shrinkage  during  the  latter  part  of  the  milking  period. 

Influence  of  Diseases. 

Relatively  little  is  known  of  the  chemical  changes  which 
milk  undergoes  from  the  influence  of  general  affections  of  ani- 
mals. We  are  in  possession  of  better  information  relative  to  the 


gg  Internal  Influences  on  the  Character  of  Milk. 


occurrence  of  specific  disease  agents  in  milk,  and  it  is  known  that 
these  pass  into  the  milk  either  directly  from  the  blood  being  then 
eliminated  with  the  milk,  or  else  they  reach  the  milk  through  sub- 
sequent contamination  of  the  milk  with  excretions. 

A  rapid  diminution  of  the  milk  yield  is  characteristic  in  all 
acute  diseases  associated  with  great  pain  and  fever,  and  in  some 
cases  a  sudden  cessation  of  the  secretion  may  be  observed. 

Whenever  the  yield  of  milk  of  a  cow  suddenly  shows  a  con- 
siderable diminution,  all  of  her  milk  should  be  excluded  from  mar- 
ket, even  though  the  animal  shows  no  visible  affection  and  before 
the  disease  can  be  recognized  as  a  general  or  specific  affection.  In 
the  sense  of  the  pure  food  law  the  milk  of  every  severely  affected 
cow  should  be  considered  unfit  for  food  without  any  further  con- 
sideration. 

Sometimes  this  unfitness  of  the  milk  is  manifested  by  strong 
objective  perceptible  changes,  as  compared  with  the  secretion  of 
healthy  animals. 

The  milk  may  become  bitter,  salty,  have  an  increase  of  ash  and 
albumin,  and  coagulate  more  rapidly  than  healthy  milk  (Jensen). 
The  fat  content  of  the  milk  is  at  the  same  time  diminished  or  in- 
creased, while  the  sugar  and  ash  contents  may  show  fluctuation. 
The  amount  of  catalase  present,  according  to  Spindler,  may  in- 
crease considerably,  especially  in  cases  of  peritonitis  and  tubercu- 
losis. The  reaction  of  the  milk  remains  acid  or  becomes  slightly 
alkaline.  According  to  Schnorf,  most  of  the  internal  affections, 
even  when  the  udder  is  not  involved,  produce  a  diminution  of 
sugar  and  proteid  contents  as  a  result  of  increased  metabolism. 
The  electrical  conductivity  of  the  milk  of  animals  with  general 
affections  is  subject  to  great  fluctuations.  After  tuberculin  injec- 
tions with  subsequent  fever,  the  milk  shows  a  slight  increase  in 
its  electrical  conductivity.  The  index  of  refraction  in  pathological 
milk  is  normal,  and  not  diminished;  the  temperature  at  which 
freezing  occurs  is  not  infrequently  higher. 

During  the  course  of  individual  diseases  the  following  should 
be  considered: 

An  elimination  of  toxins  and  toxic  products  of  metabolism 
with  the  milk  is  to  be  feared  in  all  septic  and  pyemic  diseases.  If 
with  this  there  is  a  possibility  of  contamination  with  pathological 
excretions,  as  for  instance  in  septic  metritis,  hemorrhagic  or 
ichorous  enteritis,  or  in  the  retention  of  putrid  afterbirth,  the  milk 
should  be  considered  harmful.  In  septic  metritis  the  infective 
agents  pass  from  the  uterus  into  the  meat  and  into  the  udder,  from 
which  they  may  be  eliminated.  Basenau  demonstrated  the  Bacillus 
morbificans  bovis,  a  meat  poisoning  organism  of  the  colon  typhoid 
group,  in  the  meat  during  the  existence  of  septic  metritis.  The 
stapylococci  and  streptococci  which  are  frequent  participants  in 
mixed  infections  of  the  uterus,  are  also  eliminated  with  the  milk, 
provided  the  udder  has  not  already  ceased  its  secretion. 


Influence  of  Disease. 


Milk  from  cows  affected  with  acute  and  sub-acute  intestinal 
inflammations  should  be  judged  in  the  same  way  as  milk  from 
animals  affected  with  septic  metritis. 

The  ingestion  of  milk  from  cows  affected  with  bloody  or  fetid 
diarrheas  should  be  especially  guarded  against.  The  appearance 
of  sickness  in  man  after  the  ingestion  of  such  milk  has  been  satis- 
factorily proved  by  Gaffky  and  Follenius. 

Two  assistants  and  a  helper  of  the  Hygienic  Institute  of  Giessen  drank  milk  of 
this  character  and  became  sick  with  dullness,  headaches  and  chills.  After  two  days 
diarrhea,  vomiting  and  high  fever  appeared.  The  clinical  manifestations  in  the  two 
assistants  simulated  those  of  typhoid  fever,  while  in  the  helper  they  were  similar  to 
those  of  Asiatic  cholera.  The  milk  originated  from  a  cow  affected  with  hemorrhagic 
enteritis.  Gaffky  demonstrated  rapidly  growing  and  strongly  virulent  colon  bacilli 
both  in  the  bloody  excrements  of  the  cow  and  in  the  stools  of  the  affected  patients. 

In  the  presence  of  infectious  diseases  the  milk  of  the  en- 
tire stable  should  be  withdrawn  from  use,  or  should  be  rendered 
safe  by  suitable  treatment,  as  for  instance  by  pasteurization.  Such 
milk  should  never  be  sold  as  certified  or  infants'  milk.  Jensen  ex- 
tends this  prohibition  even  to  milk  from  stables  in  which  white 
scour  of  calves,  and  other  calf  affections  of  an  infectious  nature 
have  occurred. 

Dangerous  properties  of  the  milk  should  also  be  considered  in 
the  appearance  of  other  diseases,  as  for  instance  malignant  catarrh- 
al  fever,  purulent  broncho-pneumonia,  traumatic  pericarditis,  rin- 
derpest, etc.  (Bongert).  In  all  cases  of  hemorrhagic,  purulent, 
acute  or  chronic  inflammations  of  the  kidneys  the  milk  should  be 
judged  similarly  to  milk  from  animals  with  intestinal  inflamma- 
tions. In  such  affections  the  freezing  point  of  the  milk  approaches 
zero,  and  the  refraction  index  is  lower.  At  the  same  time  these 
values  in  animals  affected  with  inflammations  of  the  kidneys  vary 
extensively. 

Special  Infectious  Diseases. 

Tuberculosis  of  animals,  especially  its  hygienic  importance, 
is  considered  here  in  connection  with  tuberculosis  of  the  udder. 
It  should  be  mentioned  at  this  point  that  some  investigators  be- 
lieve that  the  toxins  of  the  tubercle  bacillus  pass  into  the  milk.  A 
change  of  the  quality  of  the  milk  will  occur  only  in  cases  in  which 
the  advanced  chronic  affection  of  the  animal  results  in  lasting 
emaciation,  or  when  an  acute  attack  of  the  disease,  associated  with 
fever,  appears  during  the  chronic  course  of  the  disease.  In  tuber- 
culosis the  milk  may  become  bluish,  and  poor  in  fat,  the  sugar  and 
proteid  substances  may  be  diminished,  or  the  latter  may  be  even  in- 
creased (Storch).  Several  tables,  which  indicate  the  experimental 
results  of  Monvoisin,  are  taken  from  Grimmer 's  "Chemistry  and 
Physiology  of  Milk." 


Internal  Influences  on  the  Character  of  Milk. 


1000  gm.  of  milk  contained  Tuberculous  cows  without 

Healthy  cows  tuberculosis  of  the  udder. 

Acidity  as  lactic  acid 1 . 543  0 . 664  1 . 292 

Total  nitrogen   5.87  8.67  4.21 

Fat    46.5  29.6  59.7 

Sugar  43.5  29.8  43.9 

Solids   142.3  126.05  147.5 

Ash  7.3  8.2  6.7 

Chlorin  (sodium  chloride)  ...       1.4  4.13  1.05 

Freezing  Point — 0.55 

Eefraction  at  15  deg 1 . 3434  1 . 3416  1 . 3442 

In  rinderpest,  according  to  Busson,  the  amount  of  fat  and 
sugar  diminished  rapidly,  whereas  the  casein,  albumin  and  salt 
increased.  The  passage  of  the  contagion  of  rinderpest  into  the 
milk  in  a  direct  way  from  the  blood  is  probable;  the  milk,  how- 
ever, can  be  contaminated  with  certainty  through  infectious  secre- 
tions and  excretions.  Einderpest  is  of  no  practical  importance 
from  the  standpoint  of  milk  hygiene,  to  most  of  the  European 
countries  (with  the  exception  of  Turkey),  since  it  has  been  eradi- 
cated with  the  aid  of  veterinary  police  measures  and  even  in  the 
event  of  any  possible  introduction,  it  will  be  immediately  sup- 
pressed. 

Milk  from  cows  affected  with  contagious  pleuro-pneumonia 
is  supposed  to  have  caused  the  death  of  children  (Randou,  Lecujer 
and  Wiedemann).  Secretion  of  milk  is  immediately  reduced  at  the 
onset  of  this  disease,  it  becomes  poor  in  fat  and  sugar,  richer  in 
albumin  and  ash,  its  appearance  resembles  that  of  colostrum,  and 
its  taste  is  peculiar.  The  contagion  of  pleuro-pneumonia  appears 
to  pass  into  the  blood  but  rarely,  and  therefore  its  elimination  in 
the  milk  can  occur  only  exceptionally,  if  at  all.  Contagious  pleuro- 
pneumonia  is  also  subject  to  the  most  stringent  veterinary  police 
measures,  and  therefore  has  but  little  practical  importance  for 
milk  hygiene. 

Similar  conditions  prevail  with  pox  of  cattle.  This  disease 
however  demands  our  interest  for  the  reason  that  the  infectious 
agent  of  cow  pox  must  be  considered  as  a  mild  form  of  smallpox 
of  man.  Cattle  usually  become  affected  through  transmission  of 
the  disease  from  naturally  infected  men,  or  from  those  vaccinated 
with  cow  pox.  The  infection  occurs  if  during  milking  the  contagion 
of  pox  is  rubbed  into  visible  or  invisible  wounds  of  the  skin  of  the 
udder.  The  infected  teats  manifest  roundish  or  oval,  hard  papules 
of  the  size  of  a  pea,  which  after  1  to  2  days  change  into  yellowish- 
white  vesicles  of  a  mother-of-pearl  luster.  After  ripening  into  pus- 
tules which  requires  from  8  to  10  days,  the  lesions  show  a  charac- 
teristic depression  in  their  center,  the  so-called  navel  of  the  pox. 
They  either  rupture  and  suppurate,  or  dry  and  heal,  leaving  a 
superficial  scar. 

The  udder  becomes  sensitive  to  pain,  the  milk  is  thinner,  and 


Influence  of  Disease. 


of  lower  specific  gravity,  but  richer  in  albumin  (Jensen).  The 
injection  of  the  contagion  of  pox  into  the  ducts  of  the  udder  results 
in  the  development  of  pox  vesicles  on  the  walls  of  the  milk  ducts. 
After  2  to  3  days  a  swelling  of  the  udder,  with  increased  sensitive- 
ness, develops  and  the  secretion  is  changed.  It  becomes  purulent 
and  bloody  on  the  eighth  to  the  tenth  day  (Lienaux  and  Hebrant). 
Transmission  from  animal  to  animal  may  be  brought  about 
by  milking,  and  the  entire  herd  in  a  stable  may  rapidly  become  af- 
fected. The  course  of  cow  pox  is  usually  benign.  According  to 
Herz  the  milk  becomes  rich  in  cells,  contains  colostral  bodies,  and 
it  has  an  unpleasant  taste.  Careful  examination  showed  the  fol- 
lowing results : 

Beginning  of     After  13  After  40 

observations          days  days 

Specific  gravity  of  the  milk 1 . 0265  1 . 0270  1 . 0215 

Specific  gravity  of  the  whey 1 . 0245  1 . 0235  1 . 0209 

Acidity  according  to  Soxhlet-Henkel .  5.3  6.6  4.1 

Fat    5.36%  4.02%  5.54% 

Solids   13.31  11.82  12.25 

Fat-free  solids   7.95  8.81  6.72 

Ash  0.72  0.72  0.8 

Transmission  of  pox  from  cattle  to  man  is  of  course  very 
readily  possible,  and  is  not  at  all  uncommon  as  a  result  of  milking 
affected  animals.  After  the  ingestion  of  infected  raw  milk  the  pox 
exanthema  may  develop  on  the  face  (Jensen). 

The  so-called  false  or  gangrenous  variola  which  may  be  fre- 
quently observed  on  the  teats  of  fine-skinned,  fresh  milking  animals 
should  not  be  mistaken  for  true  pox.  These  eruptions  are  pro- 
duced by  the  ordinary  pus-producing  organisms,  which  have  been 
rubbed  into  the  skin  during  milking  or  have  penetrated  the  skin 
by  means  of  various  injuries.  Small  furuncles  and  skin  abscesses 
result,  which  heal  without  influencing  the  formation  or  secretion 
of  the  milk.  Healing  is  of  course  retarded  through  the  act  of  milk- 
ing, and  during  the  presence  of  the  pus  cells,  blood  and  pyogenic 
organisms  may  pass  into  the  milk  in  small  quantities.  These  false 
pox  lesions  are  not  very  important. 

Of  much  greater  importance  than  cow  pox  is  foot-and-mouth 
disease  which  sometimes  appears  extensively.  This  is  a  highly 
acute  febrile  disease  which  is  transmitted  to  cloven-footed  animals 
with  remarkable  ease.  The  most  striking  symptom  which  occurs 
in  association  with  the  disease,  the  vesicular  eruptions,  may  also 
affect  the  udder,  and  especially  the  teats. 

The  udder  swells,  becomes  painful,  and  red-bordered  vesicles 
develop  in  sizes  up  to  that  of  a  walnut,  which  burst  during  milking 
or  spontaneously,  leaving  painful  ulcers.  During  the  beginning 
of  foot-and-mouth  disease  the  yield  of  milk  is  considerably  dimin- 
ished, sometimes  one-quarter  less  than  the  usual  yield,  as  a  result 


72  Internal  Influences  on  the  Character  of  Milk. 

of  the  febrile  affection  and  on  account  of  the  inappetence  due  to 
the  pain  caused  by  the  vesicles  in  the  mouth  and  on  the  feet.  The 
effect  of  the  disease  upon  milk  secretion  varies  according  to  the 
individuals,  the  age  and  the  lactation.  Siedamgrotzky,  Weber 
and  Born  have  published  the  effects  of  the  disease  on  milk  secre- 
tion during  outbreaks  in  certain  herds.  In  43  cows  the  quantity 
of  milk  at  the  height  of  the  disease  dropped  from  745  to  364  liters, 
and  again  rose  after  the  eradication  of  the  outbreak  to  522  liters. 
Thirty  cows  of  another  herd  gave  only  30  liters  instead  of  300 
liters  of  milk  during  a  period  of  eight  days.  In  a  third  herd  the 
quantity  of  milk  dropped  from  510  to  260  liters,  later  rising  to  only 
350  liters.  Other  figures  showed  a  decrease  from  750  to  280  liters, 
with  a  subsequent  rise  to  400.  The  diminished  yield  per  cow  per 
day  was  from  5  to  6  liters  and  even  more.  In  cows  that  have  been 
milking  for  a  long  time  the  loss  in  milk  reaches  as  high  as  75 %, 
in  animals  in  the  middle  of  the  lactation  period  up  to  43%,  while 
in  fresh  milkers  it  may  amount  to  55%  (Hutyra  and  Marek). 
Sugar  and  fat  contents  diminish,  but  at  times  the  amount  of  fat 
may  become  considerably  higher.  The  volatile  fatty  acids  are 
diminished,  but  the  milk  contains  more  albumin  and  salts,  an  in- 
creased amount  of  thrown-off  epithelium,  colostral  cells,  pus  cells, 
and  also  red  blood  corpuscles  (Lavena,  Kalantar,  Herberger, 
Kreis,  Vogler  and  others).  The  catalase  content  is  increased  even 
if  the  udder  manifests  no  changes  (Bertin-Sans  and  Gaujoux). 

Honigmund  examined  five  cows  affected  with  foot-and-mouth 
disease,  one  of  which  was  not  visibly  affected  on  the  day  of  the 
examination  although  already  infected.  The  individual  data  in- 
side of  nine  davs  were  as  follows : 


Quantity          Tempera- 

Specific 

Fat  Con- 

Nitrogen- 

of Milk 

ture 

Gravity 

tents 

ous  Subs. 

Sugar 

Solids 

Ash 

15  L. 

38.7 

1 

.032 

3.05 

2 

.99 

4.24 

11 

.62 

0.74 

6  — 

7  " 

39.6 

1 

.031 

5.4 

2 

.97 

3.63 

13 

.00 

0.63 

6  — 

7  " 

38.9 

1 

.030 

4.3 

2 

.99 

3.80 

12 

.81 

0.89 

about 

8  " 

39.0 

1 

.030 

3.43 

3 

.04 

3.91 

11 

.33 

0.65 

8  — 

10  " 

38.6 

1 

.031 

3.06 

3 

.04 

4.15 

11 

.01 

0.70 

8  — 

10  " 

38.4 

1. 

,029 

2.9 

3 

.1 

4.49 

12, 

.03 

0.69 

about 

10  " 

38.6 

1 

.030 

2.84 

3 

.19 

4.57 

11 

.21 

0.71 

10  - 

11  " 

38.5 

1 

.032 

3.45 

3 

.24 

4.41 

11 

.77 

0.67 

about 

12  " 

38.4 

1 

.031 

3.25 

3 

.33 

4.38 

12 

.30 

0.70 

It  appears  also  from  the  other  investigations  of  Honigmund, 
in  which  the  animals  showed  symptoms  of  the  disease  as  early  as 
on  the  first  day  of  the  examination,  that  the  fat  and  ash  content 
is  greater  in  the  first  day  than  in  normal  conditions.  The  total 
solids  and  also  the  fat-free  solids  fluctuate  considerably. 

When  catarrh  of  the  milk  ducts  becomes  associated  with  foot- 
and-mouth  disease,  the  milk  becomes  yellowish,  of  a  rancid,  bitter 
taste,  colostrum-like,  and  similar  to  the  secretion  during  other  in- 


Foot-and-Mouth  Disease.  73 


flammatory  conditions  of  the  udder,  that  is,  slimy,  watery,  and  in- 
termixed with  coagulum. 

It  is  an  important  fact  that  milk  from  animals  which  are  af- 
fected with  foot-and-mouth  disease  will  contain  the  virus  of  foot- 
and-mouth  disease,  if  it  has  been  contaminated  by  the  vesicular 
contents.  Nocard  succeeded  in  proving,  however,  by  careful  ster- 
ile drawing  of  the  milk  from  cows  affected  with  foot-and-mouth 
disease,  that  the  milk  does  not  contain  the  virus  of  foot-and-mouth 
disease  as  it  leaves  the  udder. 

Nevertheless  it  is  not  satisfactorily  proved  that  a  direct 
elimination  of  the  virus  may  not  take  place  at  the  beginning  of  the 
febrile  state,  as  at  this  time  the  virus  is  present  in  the  blood.  If 
the  udder  itself  is  affected  by  the  eruptions  of  foot-and-mouth 
disease  it  is  hardly  possible  to  avoid  contamination  of  the  milk  with 
the  vesicular  contents.  Considering  the  ease  with  which  the  virus 
of  the  disease  is  spread,  it  may  be  assumed  that  the  entire  milk  of 
a  herd  affected  by  the  disease,  under  ordinary  conditions  of  milk 
production,  contains  the  contagion  of  foot-and-mouth  disease. 
Strict  veterinary  police  measures  must  be  inaugurated  to  prevent 
the  spread  of  the  disease.  Sale  of  the  milk  should  be  permitted 
only  after  sufficient  heating.  The  maintenance  of  a  temperature 
of  70  deg.  C.  for  one-half  hour  will  make  the  milk  perfectly  safe. 

Milk  containing  the  living  virus  of  foot-and-mouth  disease 
must  be  considered  deleterious  to  human  health,  since  it  has  been 
established  by  experiments  and  observations  that  the  disease  is 
transmissible  to  human  beings.  Vesicular  and  ulcerated  inflam- 
matory changes  of  the  buccal  mucous  membrane  with  fever  and 
general  symptoms  develop  with  possible  vesicles  and  ulcers  on  the 
hands,  arms,  breast,  lips,  ears,  and  in  the  throat.  Vomiting  and 
diarrhea  may  be  associated  with  symptoms  of  a  gastro-intestinal 
inflammation,  and  the  affection  may  even  terminate  in  death.  (Bus- 
senius  and  Siegel,  Jensen,  annual  reports  of  the  Imperial  Board 
of  Health,  Hertwig,  Stickler,  Schreyer,  Krajewski,  Walkowski,  and 
others).  Bongert  suggests  the  separation  in  dairy  stables  of  the 
non-affected,  slightly  and  severely  affected  animals  into  isolated 
groups,  and  in  order  to  reduce  the  economic  losses  as  low  as  pos- 
sible, the  milk  of  these  groups  should  be  treated  in  different  ways. 
Heated  milk  from  the  non-affected  animals  for  instance,  could  be 
utilized  as  infant's  milk.  The  milk  from  slightly  affected  animals 
could  be  marketed  as  ordinary  milk  [after  pasteurization],  while 
the  milk  from  the  severely  affected  cows  or  milk  changed  in  its 
consistence,  should  be  excluded  from  consumption  even  in  a  heated 
condition.  Even  with  this  separation  the  losses  will  necessarily  be 
high  as  a  result  of  the  enforcement  of  stringent  sanitary  regu- 
lations. 

According  to  Ebert  sour  milk  3  to  4  days  old  is  no  longer 
capable  of  transmitting  the  infection.  The  transmission  is  possi- 


74  Effect  of  Internal  Influences. 


ble  through  cheese  and  butter  (Frohner,  Ebstein,  Thiele,  Schnei- 
der, Frick,  Frohlich). 

The  general  rules  which  have  been  indicated  above  obtain  also 
in  changes  of  the  milk  in  malignant  oedema,  blackleg,  or  parturient 
blackleg  of  cattle.  Transmission  of  these  diseases  through  the 
consumption  of  milk  from  affected  cattle,  or  through  the  diseased 
products  of  contaminated  milk,  is  not  to  be  feared;  besides  milk 
production  ceases  very  rapidly  in  the  affected  animals. 

The  same  rules  should  apply  in  judging  milk  from  animals 
affected  with  hemorrhagic  septicemia,  a  disease  which  is  pro- 
duced by  a  bi-polar  bacterium.  This  disease  is  transmissible  to 
calves,  through  sucking  or  feeding  milk  from  affected  animals. 

Anthrax  of  cattle  should  also  be  mentioned.  This  runs  in  an 
acute  or  sub-acute  form,  and  as  a  rule  is  associated  with  a  sudden 
cessation  of  the  milk  secretion,  which  occurs  even  as  early  as  at 
the  beginning  of  the  fever.  The  anthrax  bacilli  only  multiply 
towards  the  end  of  the  disease  sufficiently  to  cause  a  direct  passage 
from  the  blood  into  the  milk.  If  the  secretion  has  continued  to 
some  extent  this  direct  passage  is  possible  even  if  no  hemorrhages, 
such  as  are  typical  during  the  course  of  anthrax,  have  developed 
in  the  parenchyma  of  the  udder.  The  demonstration  of  anthrax 
bacilli  in  milk  has  been  accomplished  micro scopically,  and  by 
inoculation  and  cultural  experiments,  but  not  in  all  the  cases 
which  have  been  examined  (Bollinger,  Chambrellent  and  Mous- 
sou,  Feser,  Monatzkow). 

In  severe  cases  the  milk  becomes  yellowish,  bloody  and  slimy. 
At  the  appearance  of  the  fever  the  fat  and  sugar  contents  are  in- 
creased, while  the  proteid  contents  are  diminished. 

The  danger  of  infection  through  the  ingestion  of  raw  milk  con- 
taining bacilli  is  slight,  since  the  anthrax  bacilli  are  digested  by 
the  gastric  juice.  More  dangerous  than  the  bacilli  which  may  pass 
into  the  milk  from  the  blood  are  the  anthrax  spores  which  may 
reach  the  milk  through  contamination  with  manure  of  affected 
animals,  or  through  straw  and  stable  dust,  since  the  resistant 
spores  are  not  destroyed  by  the  gastric  digestion.  The  virus  may 
also  be  present  at  times  in  normally  healthy  animals  after  they 
ingest  food  containing  anthrax  spores..  The  milk  may  become 
infective  through  contamination  with  feces  from  such  bacilli  car- 
riers. In  spite  of  the  fact  that  there  are  remarkably  frequent 
opportunities  to  obtain  milk  with  bacilli  and  spores  from  localities 
in  which  anthrax  persists  epizootically  as  a  disease  of  the  soil,  yet 
only  one  anthrax  infection  of  man  is  known  to  have  occurred 
through  the  ingestion  of  milk.  This  resulted  in  a  patient  with 
typhoid  fever,  who  after  drinking  iy2  liters  of  milk  became  affected 
with  intestinal  anthrax.  The  milk  was  derived  from  a  cow  with 
a  malignant  pustule  on  the  udder,  which  had  died  in  the  meantime 
from  anthrax. 


Rabies.  75 

Lehnert  states  that  the  calf  of  a  cow  affected  with  anthrax  re- 
mains "well,  although  it  may  suck  the  mother  through  the  entire 
course  of  the  disease. 

Even  though  milk  offers  a  splendid  nutritive  medium  for 
the  anthrax  bacillus,  an  increase  of  bacilli  only  occurs  during  the 
first  three  hours.  Keeping  the  milk  at  room  temperature  for  18  to 
24  hours,  is  followed  by  the  death  of  the  bacilli  (Caro).  At  the 
beginning  of  souring  the  vegetative  forms  of  the  virus  are  quickly 
destroyed;  the  spores  however  remain  active  (Inghilleri).  If 
anthrax  bacilli  are  cultivated  in  milk,  coagulation  occurs  under  the 
rennet  action  of  the  peptonizing  bacterial  ferments.  The  coagulum 
again  slowly  dissolves,  and  the  milk  separates  into  fat  and  whey. 

Less  important  than  anthrax  is  rabies,  as  this  disease  occurs 
much  more  rarely  in  cows.  According  to  Nocard  and  Bardach 
the  milk  of  animals  affected  with  rabies  contains  the  virus.  Never- 
theless the  danger  to  man  from  the  ingestion  of  such  milk  is  hardly 
probable,  since  it  is  impossible  to  affect  experiment  animals  by 
feeding  fresh  milk  (exceptions  are  rats  and  mice).  A  nursing 
infant  of  a  woman  affected  with  rabies  remained  well,  although 
it  was  fed  with  the  milk  of  the  patient  until  one  day  before  her 
death  (Bardach).  The  uninjured  mucous  membrane  of  the  mouth, 
pharynx,  and  the  intestinal  tract  does  not  offer  opportunity  for 
infection.  This  opportunity  is  afforded  only  when  destruction  of 
tissue  and  small  wounds  permit  the  entrance  of  the  contagion. 
Thus  for  instance  Galtier  succeeded  in  producing  rabies  through 
rubbing  brain  material  of  rabid  animals  into  the  mucous  mem- 
brane of  rabbits.  According  to  the  observations  of  Virschikowsky 
the  rabid  virus  is  destroyed  by  the  gastric  juice. 

Very  little,  or  nothing  at  all  is  known  relative  to  the  special 
relationship  of  other  infectious  diseases  to  milk,  as  for  instance 
malignant  catarrhal  fever,  croup  of  cattle,  the  blood  diseases  of 
cattle  caused  by  spirochaetes,  trypanosomes  and  piroplasma,  or  in- 
fectious vaginal  catarrh  and  infectious  abortion.  In  the  presence 
of  infectious  vaginal  catarrh  and  contagious  abortion  the  milk 
secretion  is  supposed  to  be  diminished. 

It  should  be  remembered  that  in  such  affections  the  passing 
of  the  disease  agents  from  the  blood  into  the  milk  is  possible. 
[That  the  bacillus  of  infectious  abortion  is  eliminated  by  the  milk 
has  been  definitely  established.  See  Bureau  of  Animal  Industry 
Circular  No.  216]'. 

In  a  case  of  icterus  in  a  woman  Mayer  observed  the  passage 
of  bile  acids,  especially  taurocholic  acid  into  her  milk. 

Finally  two  other  diseases  should  be  mentioned  which  may 
be  transmitted  from  animal  to  man: 

1.  Milk  Sickness.  A  rather  peculiar  disease,  called  "milk 
sickness,"  is  found  in  the  central  part  of  the  United  States,  where 
it  at  times  occurs  as  an  epidemic  among  cattle  and  people.  In 
cattle,  the  first  indication  of  disease  is  dullness,  followed  by  violent 


Effect  of  Internal  Influences. 


trembling  and  great  weakness,  which  increases  during  the  suc- 
ceeding day  until  the  animal  becomes  paralyzed  and  dies.  Through 
the  ingestion  of  flesh,  milk,  or  dairy  products  of  an  affected  animal 
the  disease  is  transmitted  to  man  or  to  another  animal,  and  at- 
tacks produced  in  this  way  most  frequently  prove  fatal.  In  man 
the  disease  develops  with  marked  weariness,  vomiting,  retching, 
and  insatiable  thirst.  Respirations  become  labored,  peristalsis 
ceases,  the  temperature  is  subnormal,  and  the  patient  becomes 
apathetic.  Paralysis  gradually  follows  and  death  takes  place 
quietly  without  rigor  mortis. 

Many  efforts  have  been  made  to  elucidate  the  question  re- 
garding the  nature  and  cause  of  this  disease,  but  although  many 
theories  have  been  discussed  none  of  them  has  so  far  been  general- 
ly accepted.  Some  investigators  hold  that  the  disease  is  of  micro- 
organismal  origin,  some  that  it  is  due  to  auto-intoxication,  while 
others  think  it  is  caused  by  vegetable  or  mineral  poisons  All 
seem  to  agree,  however,  that  the  disease  is  limited  to  low,  swampy, 
uncultivated  land,  and  that  the  area  of  the  places  where  it  occurs 
is  often  restricted  to  one  or  a  few  acres.  Furthermore,  when  such 
land  or  pastures  have  been  cultivated  and  drained  the  disease  dis- 
appears completely. 

The  discovery  of  a  new  focus  of  this  disease  in  the  Pecos  Val- 
ley of  New  Mexico  in  November,  1907,  gave  Jordan  and  Harris  the 
opportunity  of  studying  this  peculiar  affection  by  modern  bacter- 
iological methods.  As  a  result  they  have  succeeded  in  isolating 
in  pure  cultures  from  the  blood  and  organs  of  animals  dead  of 
this  disease  a  spore-forming  bacillus  which  they  name  "Bacillus 
lactimorbi."  With  this  bacillus  they  have  reproduced  in  experi- 
ment animals  the  symptoms  and  lesions  peculiar  to  milk  sickness 
or  trembles,  and  from  these  animals  the  same  organism  has  been 
recovered  in  purity.  It  therefore  appears  to  have  been  demon- 
strated that  the  bacillus  in  question  is  the  probable  cause  of  the 
disease.  As  Jordan  and  Harris  have  already  indicated,  more  com- 
prehensive studies,  based  on  a  larger  supply  of  material,  are 
desirable  in  order  that  the  many  obscure  and  mystifying  features 
connected  with  the  etiology  of  this  rapidly  disappearing  disease 
may  be  elucidated. 

From  the  above  facts  it  seems  evident  that  milk  sickness  is  an 
infectious  disease  communicable  to  man,  and  the  cattle  owners 
should  therefore  not  be  permitted  to  make  use  of  the  meat  or  milk 
of  affected  animals  for  human  consumption.  Trans.] 

2.  Malta  Fever.  On  the  coast  of  the  Mediterranean,  in  South 
Africa,  India,  China,  Philippines,  America,  and  especially  on  the 
Island  of  Malta,  there  occurs  in  goats  a  disease  which  exists  in 
the  animals  without  producing  any  or  at  most  only  very  slight 
symptoms.  Cows  may  also  possibly  be  affected.  'The  infected 
animals  eliminate  for  months,  frequently  at  intermittent  periods, 
the  virus  of  the  disease  (Mlcrococcus  melitensis,  Bruce).  Follow- 


Mastitis.  77 

ing  the  ingestion  of  such  milk  " Malta  Fever"  develops  in  man.  It 
lias  a  protracted  course  with  recurrences,  and  is  accompanied  by 
anemia,  headaches,  rheumatic  pains,  constipation  and  swelling  of 
the  joints.  Malta  fever  terminates  fatally  in  about  3%  of  the 
cases.  The  goats  show  on  postmortem,  swelling  of  the  spleen 
and  lymph  glands,  frequently  also  inflammations  of  the  kidneys 
and  lobular  pneumonia.  The  virus  is  relatively  resistant  against 
souring  of  the  milk,  but  at  70  deg.  C.  it  dies  in  10  minutes. 

According  to  Zammit  about  10%  of  all  the  goats  on  the  Island 
of  Malta  eliminate  the  virus,  while  50%  of  the  animals  show  by 
the  agglutination  test  that  they  are  or  have  been  under  the  influ- 
ence of  the  Micrococcus  melitensis. 

We  are. in  possession  of  better  information  concerning  the 
changes  which  milk  undergoes  in  inflammations  of  the  udder  than 
we  have  regarding  the  effect  on  the  milk  secretion  as  a  result  of 
general  diseases,  or  regarding  the  importance  of  milk  from  affected 
animals  from  a  hygienic  standpoint. 

Changes  in  Appearance,  Consistence,  Contents,  Etc.,  During  an 

Attack  of  Mastitis. 

Relatively  very  little  is  known  as  to  the  influence  of  the  dis- 
eases of  the  udder  on  the  chemical  and  physical  character  of  the 
milk,  although  it  is  well  known  that  with  the  changes  in  function 
and  condition  of  the  organ  the  product  is  also  changed,  as  com- 
pared with  the  product  of  the  normal  gland.  Even  in  the  same 
disease  the  product  varies  in  accordance  with  the  intensity,  dura- 
tion and  the  extension  of  the  disease,  the  same  as  it  naturally 
varies  in  accordance  with  the  nature  of  the  injury  to  which  the 
parenchyma  is  subjected.  As  a  result  of  these  conditions  the  re- 
sults of  the  data  of  different  authors  vary  considerably. 

It  may  be  said  in  general  that  in  affections  of  the  udder  the 
proportion  of  the  proteids,  sugar,  salt,  fat,  and  enzymes  in  the 
milk  becomes  altered  and  that  the  relation  of  the  individual  pro- 
teids, the  salts  and  the  enzymes,  also  undergoes  fluctuations.  In 
acute  and  greatly  extended  chronic  inflammations,  both  fluid  and 
cellular  constituents  of  the  blood  may  pass  into  the  milk,  cells  of 
the  parenchyma  are  thrown  off,  coagulation  sets  in,  and  briefly, 
the  milk  changes  more  or  less  rapidly  in  appearance,  taste  and 
contents,  so  that  it  deviates  considerably  from  the  milk  of  healthy 
cows. 

At  times  none  of  these  characteristics  appears,  especially  in 
the  early  stages  of  chronic  inflammations  of  the  udder,  or  after 
the  subsidence  of  the  acute  symptoms,  and  it  is  then  only  possible 
with  the  aid  of  certain  methods  of  examination  to  differentiate 
such  affected  milk  from  normal. 

Therefore  of  special  importance  to  milk  hygiene  are  the 
chronic  inflammations,  and  inflammatory  stages  in  which  the 


78  Effect  of  Internal  Influences. 

changes  of  the  secretion  appear  slowly,  and  relatively  late,  while 
inflammations  of  an  acute  character  very  quickly  produce  a  tre- 
mendous change  in  the  secretion,  the  mixing  of  which  with  market 
milk  would  be  the  grossest  negligence.  It  is  to  be  regretted  that 
such  cases  occur. 

Appearance  of  affected  milk :  In  forms  of  inflammation  which 
are  associated  with  rapid  development,  painful  swelling  and  in- 
creased temperature  of  the  udder,  the  milk  usually  has  a  bloody 
discoloration,  later  becoming  yellow  (colostrum-like),  and  finally 
changes  into  a  custard,  or  honey-like  secretion,  in  which  thick, 
yellow  and  yellowish-brown  flakes  are  suspended  in  a  more  or  less 
clear  serum  or  plasma. 

Such  changes  are  observed  in  samples  of  milk  in  acute  forms 
of  mastitis,  through  infection  of  bacteria  of  the  colon  group,  in 
mixed  infections,  in  acute  attacks  or  in  great  extension  of  strep- 
tococcic  mastitis,  and  in  infections  with  the  Bacillus  pyogenes,  etc. 

In  chronic  affections  the  milk  changes  only  slightly  or  not  at 
all  during  the  beginning  of  the  disease,  or  it  may  appear  normal 
long  before  the  disease  as  such  is  considered  cured.  If  such  nor- 
mal appearing  milk  from  affected  quarters  is  allowed  to  stand 
for  several  hours  a  white,  yellowish-white  or  yellowish  sediment 
settles  to  the  bottom.  At  the  same  time  the  quantity  of  cream  is 
increased  and  changed,  appearing  yellowish,  tenacious,  and  when 
shaken  it  assumes  a  cloudy  or  wavy  appearance.  If  the  migration 
of  the  pus  corpuscles  from  the  blood  vessels  becomes  more  inten- 
sive the  milk  appears  thick,  yellowish,  cream-like,  and  after  stand- 
ing separates  into  a  yellowish-white  to  ocher  colored  sediment, 
which  may  amount  to  two-thirds  or  more  of  the  entire  mass,  and 
into  a  dark,  transparent,  yellowish-grey  to  greenish-yellow  skim 
milk.  The  sediment  layer  is  at  times  increased,  at  other  times 
decreased.  The  cream  becomes  granular,  shredded,  and  tenacious. 
If  red  blood  corpuscles  are  eliminated  in  great  numbers  they  col- 
lect in  the  form  of  a  red  disc  on  the  yellow  to  yellowish-brown  base, 
which  is  composed  of  leucocytes  and  coagulation  masses.  In 
hemorrhagic  stages  of  the  inflammation  the  milk  is  pinkish  or 
brownish-red;  by  sedimentation  it  separates  into  a  Bordeaux-red 
or  rust-colored  precipitate,  and  a  pinkish-red  layer  of  cream  over 
the  reddish-gray  skim  milk. 

In  other  cases  the  milk  becomes  grayish  and  watery,  and  only 
a  few  thin  conglomerates  and  fat  globules  indicate  the  layer  of 
cream. 

Cream  and  sediment  are  especially  rich  in  cells  in  all  forms 
of  inflammation.  Epithelial  cells  are  desquamated  into  such  milk 
in  the  form  of  colostral  cells,  or  entire  epithelial  bands,  and  numer- 
ous polynuclear  leucocytes,  besides  single  epithelial  cells,  into 
which  macrocytes  penetrate  (albuminophores),  erythrocytes,  cell 
debris,  fragments  of  nuclei,  as  well  as  Nissen's  globules  are  found. 

Besides  concrements  of  the  most  varied  quality,  casein  and 


Mastitis.  79 

fibrinous  flakes   appear  (Zschokke,   de  Bruin,   Kitt,  Sven  Wall, 
Doane,  Eussell  and  Hoffman,  Ruhm,  Ernst,  Bahr  and  others). 

The  taste  of  milk  from  affected  quarters  of  the  udder  is  also 
affected  markedly,  the  milk  becoming  salty,  bitter,  and  pungent. 
According  to  Craandijk  in  67%  of  cases  the  taste  of  the  milk 
changes  in  streptococcie  mastitis. 

From  the  appearance  which  the  affected  quarter  manifests, 
as  compared  with  healthy  quarters,  from  the  change  in  the  behav- 
iour of  the  animal,  from  the  varying  quantity  of  the  secretion 
against  the  quantity  from  healthy  quarters  or  the  previous  yield 
of  the  same  quarter,  the  milker  becomes  suspicious  of  the  existence 
of  an  abnormal  condition  in  the  suspected  quarter,  and  the  tasting 
test  reveals  a  salty,  bitter  taste  which  assures  him  of  the  appear- 
ance of  a  change  in  the  activity  of  the  gland.  If  the  udder  secre- 
tion could  be  examined  on  the  hollow  of  the  hand  before  being 
milked  into  the  pail,  in  order  to  determine  the  possible  presence 
of  flakes,  etc.,  as  should  be  the  duty  of  the  milkers,  then  the  mix- 
ing of  such  milk  from  affected  quarters  would  not  occur  to  the 
extent  that  it  does  at  present,  as  has  been  proved  on  numerous 
occasions.  A  great  deal  would  be  gained  if  the  milk  from  those 
quarters  which  produce  a  milk  so  changed  that  its  abnormalities 
can  be  recognized  by  its  appearance  or  taste  could  be  totally  de- 
stroyed. As  a  matter  of  fact  milkers  can  much  more  readily  rec- 
ognize developing  inflammations  of  the  udder  (as  for  instance 
streptococcie  mastitis)  from  the  varying  conditions  of  the  udder,  or 
quarter,  the  quantity  of  milk,  and  the  behavior  of  the  animal,  than 
the  veterinarian  can  by  a  single  clinical  examination.  Therefore  the 
method  applied  in  practice  consisting  of  a  single  clinical  examina- 
tion of  the  cows  producing  infant  milk  at  the  time  of  purchase,  or 
every  3  to  4  weeks  is  not  sufficient  to  determine  the  presence  of  ud- 
der affections.  Periodical  examinations  of  all  cows  producing  certi- 
fied milk,  supplemented  by  tests  of  the  milk  obtained  at  the  time  of 
the  examination,  are  necessary  when  the  inspection  is  to  serve  its 
purpose. 

At  the  examination  in  the  stable  a  comprehensive  history 
should  be  taken  from  the  milkers  relative  to  the  general  condition 
of  the  cows,  their  action  during  milking,  the  condition  of  the  teats 
and  the  gland  tissue,  the  inflammatory  changes  noted,  in  fact  all 
points  which  may  offer  valuable  supplements  to  physical  examina- 
tion. One  may  learn  from  questioning  that  the  cow  milks  very 
hard  from  one  quarter,  that  she  sometimes  refuses  to  "give  down" 
her  milk,  or  that  she  "draws  up"  the  milk  or  that  recently  the 
cow  has  shown  a  tendency  to  kick  during  milking.  At  other  times 
one  may  hear  that  the  parenchyma  contains  knobs  or  lumps  or  that 
the  teats  contain  beads  or  warts,  or  are  "fleshy,"  the  quantity 
of  milk  is  diminished,  the  milk  is  sometimes  hot,  "heated,"  or 
that  the  cow  has  the  "cold  garget"  without  any  inflammatory 
indications  of  streptococcie  infections.  The  milk  is  ropy,  the 


80 


Effect  of  Internal  Influences. 


quarter  is  " blind,"  the  milk  contains  stringy  clots  and  other 
things. 

The  keeping  of  milk  records  and  the  taking  of  milk  samples 
at  least  every  four  weeks,  should  be  required  of  all  owners  of 
animals  which  produce  milk  for  city  consumption  and  those  fur- 
nishing it  to  wholesale  milk  dealers. 

Together  with  the  visible  changes  in  the  milk,  changes  of  the 
value  of  the  chemical  and  physical  properties  occur  which  have 
been  especially  studied  by  Guillebeau  and  Hess,  Schaffer  and 
Bondzynski,  E.  Seel,  Mezger,  Fuchs  and  Jesser  and  Mai  and 
Rothenfusser. 

These  changes  in  the  contents  and  properties  are  therefore 
especially  important  since  frequently  values  are  obtained  which 
suggest  adulteration  with  water.  Irreproachable  comparative  tests 
of  milk  obtained  directly  from  the  stable  may  indicate  however 
that  in  the  specific  cases  the  investigations  were  being  made  with 
abnormal  milk. 

.According  to  Schaffer  and  Bondzynski 's  examinations  the  milk  from  cows  affected 
with  mastitis  showed  the  following  values: 


Water      Solids.        Fat 

In  non-infectious 

garget  92.83  7.17  0.82 

In  yellow  gait 89.34  10.66  1.99 

In  parenchymatous 

mastitis  90.26  9.74  2.16 

In  comparison  with  healthy 

milk  ..87.75       12.25         3.4 


Pro- 
teid 

4.01 
6.00 

4.21 
3.5 


Milk 
Sugar 

0.53 

1.84 

1.01 
4.6 


Total       % 
Ash       P2O4 


0.79 
0.83 

0.97 
0.75 


7.35 


Cl. 
35.76 


19.21 
20.0 


27.79 
14-.0 


The  milk  sugar  content  was  also  considerably  diminished ;  the  amount  of  mineral 
substances  on  the  other  hand  was  increased.  Guillebeau  and  Hess  give  the  following 
values  in  milk  from  cows  with  affected  udders: 


Duratio 

1%   d£ 

2 

5 
7 
2 
2 
1% 

ll/2 
1 

8 
2 
21 

n  of  the  Disease  and  Origin 
of  the  Milk 

lys   .  .  . 

Specific      Solids. 
Gravity 

7.45 

5.15 

udder  recovering 

9.80 

1.0314       11.28 
7  69 

23.58 

from 
from 

two 
two 

affected 
affected 

quarters 
quarters 

15.88 

9.66 

from 
from 

two 
two 

affected 
affected 

quarters 
quarters 

15.88 

1.0430       20.94 
1.0379       18.18 

Fat 


0.52 
0.22 
1.95 
2.72 
1.09 
9.30 
4.50 
2.09 
0.53 
4.50 
0.97 
2.80 


Nitrog- 
enous 
subst. 
6.17 
4.26 
2.98 
3.50 
5.74 
8.53 
5.37 
6.74 
5.13 
5.37 
16.65 
7.93 


Milk 
Sugar 


0. 

4.06 

4.35 

0. 

4.68 

5.14 

2.09 

5.14 
2.61 

2.04 


Ash 


0.85 
0.82 
0.81 
0.70 
0.87 
1.07 
0.87 
0.85 

0.87 
0.71 
0.91 


In  most  cases  the  specific  gravity  is  lower  (Seel,  Mezger,  Fuchs  and  Jesser)  and 
approaches  the  normal  only  towards  the  end  of  the  disease.  In  mixed  milk  from  all 
four  quarters  the  specific  gravity  is  less  influenced. 

The  quantity  of  fat,  according  to  Seel,  and  in  some  cases  of  Mezger,  Fuchs  and 
Jesser,  is  very  much  reduced.  The  latter  authors  emphasize  the  fluctuation  of  the  fat 
in  sudden  jumps.  The  experience  of  the  official  milk  control  station  in  Munich  also 
gives  similar  results,  at  the  beginning  of  the  affection  frequently  finding  abnormally 
high  or  again  abnormally  low  fat  contents  of  the  milk. 


Mastitis.  g]^ 

The  amount  of  milk  sugar  as  a  rule  is  reduced,  and  rises  only  with  the  appearance 
of  recovery. 

The  solids  are  likewise  usually  diminished ;  the  fat-free  substance  is  also  and  only 
becomes  increased  after  signs  of  recovery  have  been  noticed. 

The  amount  of  proteid  coagulable  by  heat  frequently  increases  enormously,  as 
compared  with  the  contents  of  casein  which  diminishes. 

The  ash  content  on  the  average  is  increased.  Eelative  to  the  composition  of 
the  ash  the  data  appear  to  te  contradictory.  Although  Seel  found  in  15  cases  out  of  18 
a  diminution  of  chlorides  against  an  increased  quantity  of  P2O5  Mezger,  Fuchs  and  Jesser 
observed  an  increase  of  the  chlorine  content  and  a  diminution  of  the  phosphoric  acid, 
while  Steinegger  and  Allemann  found  that  the  amount  of  P2O5,  CaO,  KoO  and  MgO 
diminishes,  in  general,  while  the  quantity  of  CL,  No2O  and  SO3  increases.  According  to 
Hashimoto  the  ash  of  abnormal  milk  closely  approaches  the  ash  of  blood  serum  (0.78%) 
consisting  of  8.9863  K2O;  36.544  Na2O;  7.44  CaO:  1.738  MgO:  17.380  P2Or,  and 
33.627%  CL 

The  reaction  of  affected  milk  is  mostly  alkaline  (Seel,  Merger,  Fuchs  and  Jesser, 
Hoyberg,  Auzinger,  Ernst),  or  more  rarely  acid  (Zschokke,  Henkel,  Wyssmann  and 
Peter,  Ernst).  The  determination  of  acidity  is  recommended  by  Plant  as  a  means  for 
the  diagnosis  of  udder  affections. 

Independently  from  the  degree  of  acidity,  the  coagulability  on  the  addition  of 
alcohol  is  frequently  considerably  increased  but  not  always,  and  in  some  cases  not  con- 
stantly. (Henkel,  Rullmann  and  Trommsdorff,  Auzinger). 

The  refractability  of  the  calcium  chloride  serum  not  infrequently  suffers  con- 
siderable changes  upward  and  downward.  Eipper,  Ertel,  Mairhofer,  Schnorf,  Mai  and 
Rothenfusster,  Henkel,  Mezger,  Fuchs  and  Jesser  found  considerable  changes  in  this 
respect  and  proved  that  the  daily  variations  in  the  refraction  may  be  very  great  in  milk 
of  individual  quarters,  and  even  in  the  full  milk  of  an  animal.  Frequently  however  the 
refraction  of  the  calcium  chloride  serum  shows  no  change  when  compared  with  the 
milk  of  healthy  animals. 

The  same  variation  obtains  in  the  lowering  of  the  freezing  point  of  milk  from 
affected  quarters;  the  values  may  be  considerably  higher  than  that  of  healthy  milk, 
or  on  the  other  hand  they  may  be  lower.  More  frequently  a  high  value  is  observed 
(Schorf,  Quirand  and  Laserre,  Crispo,  Bertozzi,  Pins).  According  to  Schnorf  the  elec- 
trical conductivity  is  always  increased,  never  normal  or  lower.  •  According  to  Bonnema 
the  increase  of  chlorides  results  in  an  increase  of  the  electrical  conductivity. 

A  change  in  the  contents  of  original  ferments  appears  very 
early  during  the  affection,  together  with  an  increase  of  cellular 
elements,  especially  leucocytes  (Zschokke,  Bergey,  Trommsdorff 
and  Rullmann),  and  fibrinous  flakes  (Doane,  Eussell  and 
Hoffmann). 

According  to  Konirig  the  increase  of  the  catalase  content  in 
freshly  obtained  milk  is  an  indication  of  the  affection  of  the  ud- 
der, provided  the  colostral  period  has  passed.  The  publications 
of  Spindlers  and  Rullmann  (who  were  enabled  to  obtain  asepti- 
cally  milked  samples  with  which  to  work)  and  the  author's  obser- 
vations confirm  Koning's  findings.  The  author  observed  that  in 
slight,  local  affections  of  a  chronic  nature,  without  febrile  mani- 
festations, the  content  of  catalase  usually  runs  parallel  with  the  cell 
content,  and  it  rises  when  there  is  an  especially  marked  throwing 
off  of  epithelia  (presence  of  typical  colostral  cells). 

The  faculty  of  splitting  up  added  starch  solution  likewise  in- 
creases in  milk  from  affected  udders  as  compared  with  that  from 
healthy  udders.  There  are  no  observations  relative  to  the  quanti- 
tative effects  of  peroxydase.  According  to  Weichel  the  peroxy- 
dase  content  of  affected  milk  from  an  artifically  affected  goat  dis- 
appeared, whereas  the  healthy  milk  gave  the  guaiac  reaction. 

6 


Effect  of  Internal  Influences. 


The  reaction  again  appeared  when  the  secretion  became  of  a  milk- 
like  consistency. 

Affected  milk  behaves  in  various  ways  on  the  application 
of  f  ormalin-methylene  blue  solution  ;  frequently  a  very  rapid  decol- 
oration of  Schardinger's  reagent  may  be  observed  (Rullmann,  Sas- 
senhagen,  Rievel).  Sometimes  in  typically  changed  samples  the 
reduction  does  not  take  place  (author's  observation). 

As  the  above-mentioned  enzymes  (not  amylase),  at  least  in 
part  may  appear  to  be  brought  on  by  bacterial  action,  their  abnor- 
mal presence  in  milk  has  a  diagnostic  importance  only  in  freshly 
milked  samples.  The  case  is  different  with  the  complement  con- 
tent. As  indicated  in  the  chapter  on  antigens,  blood  constituents 
pass  directly  into  the  milk  during  periods  of  physiological  and 
pathological  irritations.  Therefore  in  mastitis,  as  proved  by 
Bauer  and  Sassenhagen,  complements  are  demonstrable  in  the 
milk.  This,  according  to  Sassenhagen,  is  possible  even  in  affec- 
tions in  which  the  Trommsdorff  value  of  the  centrifugalized  cells 
per  1000  parts  of  milk  is  still  remarkably  slight. 

The  alkaline  reaction  of  affected  milk,  the  altered  proportions 
of  mineral  salts,  at  times  the  passing  into  the  milk  of  bloody  parti- 
cles, and  the  diminution  of  casein,  reduce  the  coagulability  of  the 
milk  towards  added  rennet.  Affected  milk  therefore  generally 
utilizes  a  considerably  larger  quantity  of  rennet  than  normal  milk 
before  it  becomes  coagulated  (Schern). 

The  spontaneous  coagulation  of  affected  milk  also  appears  to 
be  considerably  delayed. 

Infectious  Agents  of  Mastitis. 

Nocard  and  Mollereau,  Kitt,  Lucet,  Bang,  Guillebeau  and 
Hess,  Zschokke,  Jensen,  Streit,  Glage  and  Sven  Wall  have  offered 
sufficient  information  regarding  the  infectious  agents  of  the  dif- 
ferent forms  of  mastitis. 

Most  cases  of  mastitis  are  produced  by  streptococci;  they 
consist  of  chronic  inflammations  of  one  or  more  quarters  of  the  ud- 
der. The  disease  is  of  relatively  small  influence  on  the  general 
condition  of  the  animal. 

Bacilli  of  the  coli-aerogenes-paratyphus-paracolon  groups  pro- 
duce highly  acute,  parenchymatous  lesions.  The  general  condition 
is  severely  influenced  through  infections  by  bacteria  of  the 
paratyphus-B  group.  Locally  a  gangrenous,  septic  mastitis  de- 
velops with  this  infection,  and  the  milk  is  markedly  ichorous, 
while  in  colon  infections  the  secretion  is  of  a  serum-like  character 
(Weichel). 

A  third  form  of  inflammation  of  the  udder,  also  of  a  chronic 
nature,  is  produced  by  a  representative  of  the  group  of  the 
Bacillus  pyogenes,  Sven  Wall's  pyobacillosis  of  the  udder.  The 
Bacillus  pyogenes  colonizes  with  a  special  predilection  in  the  pres- 


Streptococcic  Mastitis.  33 


ence  of  streptococci  or  staphylococci,  and  in  these  mixed  infections 
causes  severe  necrotic  inflammations  of  the  udder,  and  may  con- 
tinue to  produce  chronic  mastitis  in  the  affected  udder  tissue  after 
the  disappearance  of  the  other  bacteria. 

Other  forms  of  mastitis  are  produced  by  tuberculosis  and 
actinomycosis,  and  they  usually  result  through  emboli  of  the  in- 
fective agents.  They  may  be  of  a  traumatic  origin  (actinomycosis) 
induced  by  irritation  with  particles  of  straw,  or  barley  beards. 

Furthermore  all  possible  infective  agents,  as  for  instance 
the  Bacillus  necrophorus,  may  be  found  in  inflammations  of  the 
udder,  either  independently  or  as  mixed  infections. 

Only  the  more  important  infections  of  the  parenchyma  will 
be  described  here. 

Streptococcic  Mastitis. 

By  far  the  most  widely  spread  type  is  the  Streptococcic  mas- 
tisis,  described  by  Sven  Wall  as  streptomycosis  of  the  udder. 

The  works  of  Bergey,  Craandijk,  Trommsdorff  and  Rullmann, 
Kunze,  Eussell  and  Hoffmann,  Savage,  Riihm,  and  Ernst  give  gen- 
eral information  on  this  condition.  The  disease  is  either  sporadic 
or  epizootic  among  the  animals  of  a  stable  according  to  the  stable 
conditions.  The  disease  may  attain  an  especially  wide  distribu- 
tion when  the  secretion  of  the  affected  quarter  is  milked  upon  the 
floor  or  into  the  bedding,  and  the  milkers  fail  to  wash  their  hands, 
both  bad  practices  which,  it  is  to  be  regretted,  are  quite  common. 

Zschokke,  Jensen,  Bang,  and  Sven  Wall  proved  experi- 
mentally that  bacteria  injected  into  the  cistern  penetrate  even  into 
the  farthest  alveoli  in  from  2  to  24  hours. 

By  inoculating  with  strains  of  streptococci  of  different  ori- 
gin varying  reactions  may  be  produced  in  the  udder  (Bang:  Strep- 
tococci equi  and  Streptococci  agalactice;  Gminder :  streptococci  of 
the  stable  air  and  of  infectious  vaginal  catarrh).  The  manifesta- 
tions also  vary  after  the  injection  of  individual  strains  into  the 
same  animals,  and  from  injections  of  the  same  strain  into  various 
animals.  In  other  words  the  course  of  the  disease  varies  in  ac- 
cordance with  the  virulence  of  the  organism,  the  resistance 
of  the  body,  and  the  extent  of  the  local  invasion  which  again  is 
influenced  by  the  lactation  period.  According  to  de  Bruin  fresh 
milking  animals  more  frequently  become  affected  with  the  acute 
form  having  inflammatory  manifestations,  while  in  old  milking 
animals  the  disease  confines  itself  mostly  to  the  altered  appearance 
ot  the  secretion. 

The  result  of  the  disease  is  that  sooner  or  later  the  affected 
part  of  the  gland  becomes  destroyed. 

Sometimes  the  streptococci  remain  for  weeks  in  the  folds  of 
the  mucous  membrane  of  the  cistern  without  infecting  the  par- 
enchyma ;  in  other  cases  again  the  entire  quarter  quickly  becomes 
affected.  Unfortunately  the  disease  does  not  often  subside  even 


g4  Effect  of  Internal  Influences. 

through  the  physiologically  dry  period,  and  the  affection  re-ap- 
pears immediately  after  parturition. 

The  destruction  of  all  streptococci  involves  a  difficult  task  for 
the  entire  body.  The  dissolution  of  the  streptococci  progresses 
only  very  slowly  even  in  actively  or  passively  immunized  animals. 
Living  streptococci  may  be  demonstrated  in  the  abdominal  cavity 
of  test  animals,  many  hours  after  an  intra-peritoneal  injection. 
Not  infrequently  a  delayed  death  appears  in  apparently  recovered 
animals  (v.  Lingelsheim).  The  long  streptococci  appear  to  rep- 
resent specially  adapted  forms  which  have  great  tenacity.  Never- 
theless at  times  recovery  takes  place.  According  to  Zschokke  the 
relation  between  recovered  and  unrecovered  cases  is  as  7 :5. 

According  to  the  experience  of  the  author  in  practice,  infectious 
mastitis  is  not  curable,  or  only  with  the  greatest  difficulty,  and  if 
so,  always  with  a  loss  of  productiveness,  which  even  remains  after 
the  physiologically  dry  period.  The  chronic  irritation  causes  a 
change  in  the  connective  tissue  structure  of  the  parenchyma  of  the 
udder  so  that  the  usual  development  of  the  gland  during  pregnancy 
cannot  take  place.  The  principal  aim  in  treatment  therefore 
should  be  prompt  drying  of  the  suspected  udder,  in  order  to  make 
possible  the  most  rapid  and  most  complete  recovery,  which,  ac- 
cording to  Zschokke  may  be  expected  only  when  the  quarter  has 
been  allowed  to  remain  dry  for  a  long  time. 

This  is  also  necessary  in  order  to  prevent  a  spread  of  the 
disease,  which  is  to  be  feared  since  the  hands  of  the  milkers  and 
milking  upon  the  straw  may  transmit  the  infective  agent  to  other 
quarters.  Care  should  be  taken  therefore  to  keep  the  milk  from 
the  healthy  quarters  of  the  udder  separate  from  the  secretion  of 
the  affected  quarter. 

As  long  as  the  most  primitive  requirements  of  clean  milk 
production  on  the  part  of  the  milkers  are  so  carelessly  neglected, 
which  unfortunately  has  been  the  case  up  to  the  present,  the  im- 
mediate drying  of  the  affected  quarter  offers  the  only  means  of 
preventing  the  further  spread  of  the  disease. 

If,  however,  there  is  assurance  that  the  affected  animal  or  the  affected  quarter, 
respectively,  is  individually  milked,  and  the  milkers  follow  instructions,  an  attempt 
may  be  made  by  special  frequent  milking  (into  a  jar)  to  produce  a  hyperemia  of  the 
udder.  With  this  method  success  can  only  be  expected  in  the  early  stages. 

The  extent  of  the  spread  of  the  disease  may  become  obvious 
by  the  findings  after  examination  of  individual  herds.  In  such 
cases  it  is  necessary  to  milk  each  cow,  or  still  better  each  quarter, 
separately.  The  results  vary,  depending  on  the  technique  of  the 
examination.  The  lowest  number  of  affections  is  obtained  when 
only  a  clinical  examination  is  made.  This  therefore  does  not  suffice 
in  order  to  eradicate  the  disease  effectively,  or  to  single  out  the 
affected  animals.  The  data  of  the  different  authors  vary  relative 
to  its  occurrence.  The  following  figures  are  given  which  were 
obtained  by  systematic  examinations  of  entire  herds. 


Streptocoecic  Mastitis.  §5 


Out  of  260  animals  Trommsdorff  found  15.6%  affected,  Eiilim 
31.25%  out  of  16  animals,  Eussell  and  Hoffmann  found  in  188  sam- 
ples 50%  with  " streptococci."  Savage  found  similar  values 
(55%). 

The  author  examined  from  April  1,  1907,  to  November,  1908, 
1697  samples  of  milk  from  individual  cows,  and  found  in  348  sam- 
ples the  typical  signs  of  streptococcic  mastitis. 

In  1908  and  in  the  following  years  he  has  demonstrated : 

1908.  No.  of  animals,  1695.     Streptococcic  cases 353 

1909.  No.  of  animals,    738.     Streptococcic  cases 301 

1910.  No.  of  animals,    597.     Streptococcic  cases 203 

1911.  No.  of  animals,    876.     Streptococcic  cases 279 

Therefore  20.6;  20.9;  40.6;  34  and  31.8%,  respectively,  of 
the  animals  were  found  to  be  affected  with  streptococcic  infections 
of  the  udder. 

If  the  milk  of  the  individual  quarters  of  the  affected  udder  is 
examined  various  stages  of  the  affection  in  the  different  parts  of 
the  udder  may  frequently  be  found.  Out  of  528  quarters  of 
animals  with  affected  udders  276,  or  52.2%,  showed  lesions  in 
individual  quarters.  39.2%  of  the  cows  had  the  disease  in  one  quar- 
ter, 25.9%  showed  it  in  two  quarters,  18.5%  in  three  quarters,  and 
16.2%  in  all  four  quarters.  According  to  Zschokke  out  of  662 
affected  quarters  193  occurred  in  one  quarter  of  the  animal,  211 
in  two,  109  in  three,  and  149  in  all  four  quarters. 

The  contamination  of  market  milk  with  the  secretions  from 
animals  with  udder  affections  is  relatively  high. 

In  spite  of  the  fact  that  proof  of  the  mixing  of  milk  from 
affected  udders  with  market  milk  is  possible  only  in  very  pro- 
nounced cases  (typical  streptococcic  chains  with  characteristics 
of  animal  origin),  nevertheless  the  following  results,  obtained  in 
examinations,  demonstrated  conclusively  that  the  secretion  from 
quarters  affected  with  streptococcic  mastitis  had  been  added  to 
the  whole  milk: 

1908,  in  352  out  of  1578  samples=22% 

1909,  in  501  out  of  1629  samples=40.5% 

1910,  in  243  out  of  1211  samples=20% 

1911,  in  432  out  of  1273  samples=33.9% 

The  hygienic  importance  of  the  affection  to  the  consumers  of 
milk  may  be  illustrated  from  the  following  data. 

I.  Hoist,  in  1894,  had  the  opportunity  of  examining  in  Chris- 
tiania  four  series  of  affections  of  acute  gastro-intestinal  catarrh. 

I.  Four  grown  persons  and  four  children  out  of  three  families  in  the  same 
street  became  affected  four  hours  after  the  drinking  of  milk  which  originated  upon  one 
farm.  Those  persons  who  drank  no  milk  or  only  that  which  had  been  boiled  were  spared 
with  the  exception  of  a  child  who  became  affected,  although  only  slightly,  after  drinking 
boiled  milk. 


gg  Effect  of  Internal  Influences. 


The  appearance  of  the  milk  showed  nothing  abnormal,  but  it  coagulated  on 
boiling  and  showed  a  tremendous  number  of  bacteria,  especially  streptococci,  which 
could  not  be  distinguished  from  the  Streptococcus  pyogenes. 

The  veterinary  examination  confirmed  the  suspicion  that  a  pus-containing  secre- 
tion was  being  yielded  by  one  cow. 

The  milk  from  the  cow  with  mastitis  on  the  day  in  question  was  added  to  the 
whole  milk  through  the  neglect  of  a  newly  hired  attendant. 

2.  Several    hours   after   the   drinking   of   raw   milk   five   persons,   and   as   found 
later   other   cases   also   became   affected   with   acute   gastro-intestinal    catarrh.     In   this 
case  a  milk  dealer  was  implicated,  and   it  was  found   on  inquiry  that  the  milk  con- 
tained secretion  from  a  cow  affected  with  streptococcic  mastitis. 

3.  According    to    the    observations    of    Johannesen    two    persons     (mother    and 
child)  became  sick  after  the  drinking  of  milk.     The  milk  was  thin,  flaky,  and  contained 
pus-like  lumps.      In   the  herd   from  which  this  milk   originated  two   cows  were  found 
to  be  affected  with  streptococeic  mastitis. 

4.  After   the   drinking   of   freshly   drawn   raw   milk   four    children   of  the   same 
family  became  affected   with  acute   gastro-intestinal   catarrh.     The  milk   appeared   ap- 
parently  normal,   but    contained    large    quantities    of   streptococci.      It    originated   in 
a  stable  from  which  on  the  day  in  question  a  cow  was  sold  on  account  of  mastitis.     The 
milk   from   this   cow   appeared   to   have  been   mixed   with  the   whole   milk   due   to   the 
neglect  of  a  new  milker   (the  regular  one  being  sick). 

The  affections  which  occurred  in  Stockholm  with  symptoms  of  fever,  dullness, 
attacks  of  fainting,  nausea,  vomiting,  diarrhea  and  cramps  in  the  calf  of  the  leg 
(nine  families  being  involved),  cannot  according  to  the  obtainable  reports,  be  de- 
clared to  be  streptococcic  infections.  The  milk,  through  the  drinking  of  which  the  cases 
could  be  traced,  originated  from  a  dairy  of  14  cows,  among  which  one  cow  had  mas- 
titis. It  is  possible  that  in  this  case  an  infection  with  bacteria  of  the  paratyphus 
group,  which  plays  an  important  part  in  the  development  of  acute  mastitis,  was  con- 
cerned. 

Further  contributions  to  the  casuistics  of  "milk-  poisoning"  were  published  by 
Jakobsen  and  Weigmann  and  Gruber. 

II.  In  1905,  Jakobsen  observed  symptoms  in  several  persons  which  he  traced  to 
the  drinking  of  milk   from   one   stable.      The   symptoms   were   diarrhea,   vomiting   and 
fever.     Out  of  17  persons,  10  who   drank  the  milk  became  affected,  while  7  who  did 
not  take  any  remained  well.     On  May  30,  1905,  other  persons  became  affected. 

The  examination  of  the  32  cows  of  the  dairy  showed  a  streptococcic  mastitis 
in  one  animal.  The  cow  was  slaughtered  and  no  further  cases  were  reported. 

III.  Edwards  and  Severn  described  an  epidemic  of  follicular  tonsilitis  which  de- 
veloped from  the  drinking  of  milk.     They  found  in  the  exudate  of  the  throat,  and  in 
the  milk,  in  addition  to  other  bacteria  pyogenic  streptococci  which  as  shown  by  the  in- 
vestigation were  also  contained  in  the  secretion  of  a  cow  affected  with  mastitis. 

[In  various  cities  of  the  United  States  epidemics  of  sore  throat 
with  swelling  of  the  cervical  lymph'  glands,  colic,  diarrhea  and 
fever  lasting  several  days  have  occurred  which  were  traced  to  the 
use  of  milk  from  cows  affected  with  streptococcic  mastitis.  Such 
milk  when  examined  was  found  to  contain  pus  and  streptococci  in 
great  abundance. — Trans.] 

IV.  Lameris  and  Harreveld  observed  an  outbreak  of  diarrhea  among  the  inmates 
of  a  hospital  after  the  drinking  of  boiled  milk,  which  in    part  was  obtained  from  cows 
affected  from  streptococcic  mastitis. 

Whether  the  authors  of  the  last  cases  are  correct  in  their  view 
that  very  likely  a  heat-resisting  toxin  brought  on  the  disease,  or 
whether  the  streptococci  might  remain  alive  in  the  milk  foam  or 
in  the  formed  membrane,  etc.,  as  suspected  by  Jensen,  it  becomes 
evident  that  boiling  does  not  carry  with  it  an  assurance  that  the 
danger  from  streptococcic  milk  is  eliminated.  If  Jensen's  sus- 
picion is  correct  a  proof  would  be  offered  that  even  the  smallest 


Table  II. 


Ernst,  Milk  Hygiene. 


Streptococcic  Mastitis.  87 


quantities  of  mastitis  streptococci  are  sufficient  for  the  production 
of  severe  intestinal  affections. 

V.  On  December  17,  1907,  a  sample  of  boiled  milk  was  brought  to  the  official 
milk  control  station  of  Munich;  about  a  half  hour  after  the  drinking  of  this  milk  the 
man  who  delivered  the  milk,  and  his  family,  as  well  as  a  neighboring  family  using  milk 
of  the  same  origin,  became  sick.  The  milk  contained  1.5:1000  streptococcic  pus.  It  orig- 
inated from  a  large  dairy.  Three  producers  and  one  distributor  were  suspected.  In 
tracing  down  the  cause  of  the  trouble  two  producers  were  found  whose  herds  contained 
six  animals  with  affected  udders,  their  milk  being  mixed  with  the  whole  milk. 

The  affection  was  marked  by  chills,  diarrhea,  headaches,  and  lasted  not  quite  an 
entire  day.  The  milk  constituted  the  only  common  food  partaken  by  all,  and  there- 
fore could  be  considered,  although  not  with  absolute  certainty,  as  the  probable  cause. 

From  the  examples  cited  it  may  be  seen  that  the  drinking  of 
milk  which  contains  the  secretion  of  streptococcic  infected  udders 
is  capable,  under  certain  conditions,  of  producing  injurious 
effects  upon  the  health  of  human  beings.  Considering  the  fre- 
quency of  the  disease,  and  the  numerous  cases  where  the  prohi- 
bition of  milking  affected  udders  into  the  whole  milk  is  disre- 
garded, it  is  to  be  wondered  at  that  affections  which  could  be 
traced  to  the  drinking  of  such  milk  are  not  observed  with  greater 
frequency. 

This  may  be  due  to  the  fact  that  the  secretion  of  affected 
'quarters  is  usually  very  greatly  diluted  with  the  milk  of  healthy 
quarters,  showing  that  the  harmful  actions  are  not  necessarily 
induced  by  the  predomination  of  the  injurious  material,  and  fur- 
ther it  may  also  be  due  to  the  fact  that  the  milk  is  mostly  used 
after  being  boiled  (Trommsdorff,  Jensen).  That  the  boiling  of 
the  milk  is  not  always  sufficient  to  destroy  the  injurious  properties 
may  be  seen  from  the  cases  of  Hoist  and  Lameris  and  van  Har- 
reveld;  the  milk  of  course  is  marketed  in  a  raw  state,  and  must 
therefore  be  judged  in  the  condition  in  which  it  is  sold. 

The  factors  which  induce  the  harmfulness  of  the  milk  from 
streptococcic  animals  are  not  known.  Whether  the  injurious 
factors  are  due  to  the  toxin  produced  by  the  streptococci  of 
mastitis,  or  to  the  products  of  the  disease,  as  for  instance  pus 
(Jensen),  or  to  streptococci  which  are  pathogenic  to  man  as  such, 
cannot  at  the  present  time  be  definitely  determined.  This,  how- 
ever, is  of  little  importance  from  a  practical  standpoint.  Some 
authors,  such  as  Petruschky  and  Kriebel,  consider  that  infected 
cows  are  the  sources  of  milk  streptococci,  and  that  these  are  the 
principal  cause  of  the  summer  mortality  of  children.  Seiffert 
considers  the  streptococci  originating  from  affected  udders  as 
more  dangerous  than  the  saprophytic  streptococci  which  contam- 
inate the  milk  as  a  result  of  unclean  milking.  This  view  was  also 
expressed  by  the  author  in  May,  1908,  and  was  confirmed  by 
Trommsdorff. 

Neither  studies  nor  animal  experiments  have  succeeded  up  to 
the  present  time  in  proving  the  harmfulness  of  the  streptococci 
by  themselves,  or  the  relationship  of  the  mastitis  streptococci  to 
human  pathogenic  strains  of  streptococci,  the  animal  experiments 


gg  Effect  of  Internal  Influences. 

offering  only  a  relative  conclusion  on  the  susceptibilityof  the 
respective  species  of  animals. 

The  differentiation  of  the  mastitis  streptococci  fron  other 
milk  streptococci  is  however,  absolutely  necessary  for  milk3ontrol 
since  only  in  the  presence  of  typical  mastitis  streptococci -an  the 
milk  dealers  be  held  responsible,  and  be  obliged  to  prevnt  the 
contamination. 

Escherich  and  Hoist  found  streptococci  in  almost  every  sample  of  tilk,  and 
Hellens  repeatedly  isolated  them  from  milk.  In  1840  in  samples  of  market  tilk  from 
Munich  and  vicinity  the  author  succeeded  in  isolating  streptococci  either  hy  culti- 
vation or  recognizing  them  by  bacteriological  examination  in  100%  of  the  ca».  Other 
investigators  confirmed  a  positive  finding  in  a  strikingly  high  percentage. 

Beck— Market  milk  of  Berlin 62  % 

Savage — 17  samples  of  market  milk 100% 

10  samples  of  market  milk 100  % 

Kaiser — Market  milk  of  Grar 76.% 

Briining — 28  samples  of  Leipsic  market  milk 93% 

Easten — 186  samples   57 

Eastles — 185  samples  from  all  parts  of  England 75  % 

The  simplest  proof  of  the  constant  occurrence  of  stre]tococci 
in  market  milk  is  the  usual  acid  fermentation  of  cow  milk  dduced 
by  streptococci. 

A  method  for  distinguishing  these  frequently  observer  strep- 
tococci from  mastitis  streptococci  has  not  yet  been  disoveredr 
either  through  the  fermentation  of  various  kinds  of  sugarsby  the 
streptococci,  or  through  the  investigations  of  creatinin  forma- 
tions, hemolytic  action,  acid  formation  or  their  actions  in  th  pres- 
ence of  various  temperatures  of  cultivation.  It  should  bi  borne 
in  mind  that  the  behavior  of  the  various  strains  of  mastiti  strep- 
tococci has  been  described  in  such  a  variety  of  ways,  that  eiter  the 
presence  of  remarkably  numerous  strains  or  a  strong  installity  of 
characteristics,  or  confusion  with  saprophytic  forms,  rast  be 
accepted. 

The  formation  of  acid  by  the  streptococci  is  sometiies  de- 
scribed as  strong  (Zschokke,  Nenski,  Groning,  Kaiser,  Heinmann, 
Miiller,  Koning),  at  other  times  it  appears  insignificant  (Sven 
Wall,Kullmaim). 

Lohnic  classes  the  streptococci  of  mastitis  with  the  gamp  of 
lactic  acid  streptococci,  especially  with  the  group  of  Strefococci 
gimtheri,  with  close  relationship  to  the  group  of  Strefococci 
rosenbach,  having  the  following  characteristics : 

"Form  of  the  cells  variable;  capsule  formation  is  frequent  and  appears  o  be  as- 
sociated in  certain  forms  with  the  presence  of  sugar  in  the  nutritive  media,  bores  are 
not  formed;  the  bacteria  are  Gram-positive;  the  intensity  of  the  growth  hi;  no  sig- 
nificance. Coagulation  of  the  milk  results,  in  these  varieties,  either  thrcgh  acid 
formation  or  through  a  rennet-like  ferment;  gas  formation  is  rare;  the  patigenicity 
varies  remarkably." 

Miiller  in  his  work  on  comparative  examinations  of  lactic  acid  bacteria  fyp.  giin- 
theri,  etc.)  presents  the  following: 

1.  "The  strains  studied  manifest  marked   differences  either  in  their  cbtural  or 
morphological   characteristics  with  the   exception  of  the  strain   causing  "SOT ;  brood'1 
among  honey  bees. ' ' 

2.  ' '  The  action  on  carbohydrates  is  practically  uniform. ' ' 


Streptococcic  Mastitis. 


89 


Fig.  17. 


3.  '  Influencing  individual  strains  relative  to  their  acid  formation  in  the  sense  of 
increasing  decreasing  it,  is  possible.     The  characteristics  which  the  freshly  isolated 
strains  jxsess  are  more  or  less  permanent." 

4.  •  There  exists  a  relation  between  the  group  of  Streptococcus  giintheri  and  the 
Streptocuws  agalactiae  since  their  capability  of  forming  acid  is  about  the  same. ' ' 

5.  '  The  oft  recurring  confusion  of  the  two  may  be  explained  by  certain  similar 
forms  o%rowth  which  both  possess. ' ' 

6.  ^The  supposition  that  the  pathogenic  streptococci  represents  lactic  acid  bac- 
teria of  to  Typ.  giintheri  which  have  adapted  themselves  to  parasitic  conditions,  is  sub- 
stantiatecby  the  findings,  since  it  was  possible  in  the  various  strains  of  streptococci  to 
produce  tinsition  forms,  which  correspond  to  the  Typ.  giintheri." 

Threfore  from  these  few  examples  it  may  be  seen  that  it  is 
impos^le  to  separate  the  streptococcus  of  infectious  mastitis  from 
the  grap  of  the  lactic  acid  streptococci.  Nevertheless  it  would  be 
a  greaterror  to  identify 
the  orihary  lactic  acid 
streptcocci  with  patho- 
genic siteptococci  of  man 
and  aniials. 

If  he  fact  is  taken 
into  consideration  that 
some  steptococci,  as  for 
instanc<that  of  Kefir,  the 
streptoocci  of  sour  milk, 
and  otbrs,  have  a  fa- 
vorableinfluence  on  the 
nutritia  of  man,  the  ne- 
cessity of  their  strict 
identificition  for  control- 
ling th<  milk  supply  is 
apparet, 

Altough  it  is  not 
possible  absolutely  dif- 
ferentiae one  strain  by 
cultural  and  biological 
charactcistics,  from  a 
culture  strain  of  differ- 
ent oriin,  nevertheless 
there  ai  certain  morphological  characteristics  of  the  streptococci 
in  the  siears  made  from  sediments,  which  are  sufficiently  constant 
to  absoitely  warrant  the  definite  assertion  that  the  streptococci 
in  certai  positive  cases  originated  in  an  infected  organ,  and  were 
not  incicntally  leading  a  saprophytic  existence  in  the  milk. 

It  hs  been  known  for  a  long  time  that  parasitic  bacteria  in 
the  aniial  body,  under  the  influence  of  the  animal's  protective 
strength  attain  certain  peculiarities  of  form  which  they  lose  under 
ordinar\cultural  conditions  (under  certain  conditions  it  is  possible 
to  cultiate  capsulated  anthrax  bacilli).  Reference  is  made  to 
the  capale  of  anthrax  bacilli  and  to  the  formation  of  botryomy- 
cotic  clurps  by  streptococcic  forms.  Consideration  of  the  question 
whethersuch  changes  of  form  in  bacteria  are  developed  as  protec- 


Sediment  of  milk,  one  day  old,  from  an  udder  affected 
with  streptococcic  mastitis;  (a)  streptococci  of  in- 
fectious mastitis,  (b)  subsequently  developed  strep- 
tococci; 1,  2,  3  and  4,  cells  from  the  udder. 


90 


Effect  of  Internal  Influences. 


tive  agents  against  the  immunizing  powers  of  the  body,  would  re- 
quire too  lengthy  a  discussion.  The  fact  should  suffice  that  strep- 
tococci originating  from  affected  udders  almost  invariably  show 
signs  of  such  transformation.  It  is  not  intended  to  assert  that  a 
steptococcus  in  milk  which  does  not  possess  these  form  peculiari- 
ties is  not  a  streptococcus  of  mastitis,  or  that  it  does  not  originate 
from  the  udder,  and  that  under  abnormal  conditions  (for  instance 
cultivation  at  37  deg.  in  raw  milk  or  in  serum)  the  streptococci 
which  are  present  could  not  undergo  changes  of  form  which  under 
certain  conditions  simulate  the  forms  of  "animal"  streptococci; 
but  for  normal  conditions  of  milk  inspection  the  morphological 
characteristics  of  animal  streptococci  offer  certain  definite  appear- 

a  n  c  e  s    of    recognition 

lg'     '  which  have  always  been 

proved  by  control  tests 
made  in  the  respective 
stables. 

These  characteristics 
are  the  following: 

The  streptococcus 
takes  on  a  diplococcus- 
like  separation,  the  cocci 
apparently  press  each 
other,  become  disc- 
shaped,  and  in  profile  ap- 
pear like  a  dash.  They 
stand  at  right  angles  to 
the  length  of  the  chain 
(compare  with  equine 
distemper  streptococci 
according  to  Rabe.)  A 
fine  capsule  is  formed 

Sediment    of    market    milk    in    which    the    typical    animal         arOlind        tll6  animal 

forms  of  streptococci  (a,  b,  c)  make  possible  a  diagnosis        millr    <af rant nr»r»nm       Ti/hir>Ti 
that   the   milk    contains   the    secretion   of   an   animal   af-  C1>     W11 

fected   with    streptococcic   mastitis   in    spite    of   the   oc- 
currence of  other  forms  of  streptococci  (d  and  e). 


is    sometimes    more,    at 
other    times     less     pro- 


nounced. This  sometimes  swells  to  a  broad  mucin  capsule  (com- 
pare Lingelsheim  on  streptococci,  Wassermann-Kolle's  Hand- 
book of  pathogenic  micro-organisms  III,  pp.  309  and  310,  and 
Sven  Wall,  p.  29).  The  endococcus,  especially  in  short  chains  is 
spherical  or  swollen  to  a  club  shape. 

With  slight  practice  one  almost  invariably  succeeds  in  dis- 
tinguishing, by  one  or  the  other  given  characteristics,  the  "animal" 
mastitis  streptococci  from  streptococci  which  have  gained  access  to 
the  milk  accidentally  (even  though  they  may  also  possibly  be  de- 
scended from  ' '  animal ' '  mastitis  cocci) . 

In  this  way  the  author  succeeded,  from  April,  1907,  to  Novem- 
ber, 1908,  in  demonstrating  by  the  aid  of  smears  that  secretions 
from  cows  with  streptococcic  mastitis  wrere  mixed  with  market 


Streptococcic  Mastitis. 


91 


milk.     Out   of   1840   microscopically  examined   samples   336,  or 
18. 26%  showed  the  presence  of  such  an  infection. 

In  91  cases,  or  4.945%  the  changes  were  not  very  pronounced; 
later  control  however  proved  that  milk  from  cows  affected  with 
yellow  garget  had  been  mixed  with  these  shipments. 

18 . 26  %  +  4 . 945  %  =  23 . 205  % ,  proved  contaminated  with 
streptococcic  pus  out  of  1840  milk  samples. 

Miiller  intended  in  his  work  to  distinguish  milk  streptococci, 
especially  the  streptococci  of  mastitis,  from  strains  of  streptococci 
pathogenic  to  man.  In  confirmation  of  the  work  of  Nieber,  Fischer 
and  Berger,  Miiller  came 

to  the  conclusion  that  the  Fis-  19- 

recognition  of  milk  strep- 
tococci pathogenic  to  man 
is  impossible.  Although 
milk  streptococci  as  a 
rule  coagulate  milk  some- 
what more  quickly,  there 
are  also  strains  which 
coagulate  milk  somewhat 
more  slowly,  and  strains 
which  dissolve  the  blood 
cells  in  Schottmiiller's 
blood  agar,  and  these  in. 
their  agglutination  value 
stand  very  close  to  the 
pathogenic  streptococci 
of  man,  that  is,  they  ag- 
glutinate even  in  dilu- 
tions of  the  serum  of 
1:400—800.  At  the  same 
time  several  of  the  abso- 
lutely pathogenic  strains 
fail  to  give  any  agglu- 
tination, and  other  ap- 
parently saprophytic  va- 
rieties give  a  higher  ag- 
glutination value.  Bau- 
mann  proved  that  there  is  no  uniform  agglutination  value  of  the 
individual  kinds  of  streptococci,  and  that  spontaneous  agglutina- 
tion frequently  appears  in  tests  of  their  cultures. 

Together  with  Horauf,  the  author  found  that  mastitis  strains 
show  similar  characteristics  on  Schottmiiller's  blood  agar  to  the 
less  pathogenic  strains  of  man,  a  fact  which  has  recently  been  con- 
firmed by  Grminder.  Lingelsheim  makes  the  statement  that  strepto- 
cocci producing  toxins  are  always  obtained  from  subacute  and 
chronic  processes. 

Acid  formation  and  milk  coagulation  are  common  to  the  entire 


SS& 

*<* 


Sediment    of    red    milk.     Many    red    blood    corpuscles, 
several    polynuclear   leucocytes    and    colostral    cells. 
Streptococcus   brevis   with    capsules.      1  X  1000. 


92 


Effect  of  Internal  Influences. 


group  of  pathogenic  streptococci.  Of  the  pyogenic  strains  of  man, 
according  to  Andrewes,  the  Streptococcus  pyo genes  and  the  Strep- 
tococcus mitis  produce  acidity  without  coagulation.  Sven  Wall 
proved  these  characteristics  from  the  mastitis  strains  isolated  by 
him.  According  to  Adametz,  the  mastitis  cocci  sometimes  coagulate 
very  intensely,  the  same  as  is  the  case  with  the  streptococci  of 
enteritis  of  sucklings  (Petruschky).  The  fermentation  in  various 
sugars  using  Gordon's  bouillon  mixtures,  varies  greatly  with  the 
different  pathogenic  streptococci  and  milk  streptococci,  so  that  the 
possibility  of  differentiation  by  this  means  is  quite  impossible, 
which  is  likewise  the  case  by  testing  their  virulence  on  small  test 

animals.  Pathogenic 
strains  may  at  times  show 
great  variations  of  viru- 
lence, while  according  to 
Heinemann  strains  of  the 
Streptococcus  lacticus 
may  become  virulent  by 
passage  through  rabbits, 
until  they  will  produce 
changes  in  rabbits  which 
correspond  in  their  ap- 
pearance, extension  and 
character,  to  those  caused 
by  pyogenic  strains  re- 
covered from  man. 
Through  their  action  on 
animal  bile,  or  on  sodium 
taurocholate,  Mandel- 
baum  differentiates  the 
Streptococcus  mucosus 
and  Pneumococcus  from 
Streptococcus  pyogenes 
and  other  streptococci 
(Neufeld,  v.  Levy).  The 
author  used  the  mastitis 
strains  he  had  on  hand 
on  cattle,  hog,  horse  and 
chicken  bile,  but  failed  to  observe  either  a  clearing  of  the  culture 
media  or  an  influence  upon  the  form  and  appearance  as  shown  by 
the  microscope. 

The  establishment  of  the  "virulence  number"  through  phag- 
ocytic  experiments  also  fails  to  yield  the  desired  result. 

In  short  up  to  the  present  time  the  absolute  separation  of 
culture  strains  of  varied  origin,  the  differentiation  of  saprophytic 
streptoccoci  from  mastitis  streptococci,  and  these  from  pathogenic 
streptococci  of  man  has  not  been  successfully  accomplished.  We 
have,  however,  in  certain  morphologic  indications,  for  instance 


Sediment  of  milk  from  an  udder  with  acute  inflammation. 
Short   forms   of   streptococci.      1  X  1000. 


Streptococeic  Mastitis. 


the  cross-position  of  the  segments,  the  capsule-like  covering  ancf 
other  characters,  a  way  of  distinguishing  streptococci  originating 
in  the  udder  of  an  animal  from  such  as  have  subsequently  gotten 
into  the  milk.  If  these  distinguishing  signs  are  present  then  smears 
from  the  sediment  of  market  milk  permit  the  deduction  that  secre- 
tion from  an  affected  udder  has  been  included  in  the  milk.  If,  on 
the  other  hand,  these  signs  are  not  present  in  the  streptococci  of  the 
milk,  it  cannot  be  asserted  that  the  milk  is  not  contaminated  with 
the  secretion  of  affected  udders. 

Although   it    is    not 

known   what    factors  Fis-  21. 

(streptococci,  toxins,  in- 
flammatory products) 
convey  the  unwholesome- 
ness  to  the  milk,  and  al- 
though in  spite  of  the  fre- 
quent occurrence  of  mas- 
titis injurious  effects  re- 
sult with  relative  rarity, 
nevertheless  the  secretion 
from  udders  affected  with 
streptococcic  mastitis, 
and  mixed  milk  which  is 
contaminated  with  such 
secretion  should  be  con- 
sidered capable  of  im- 
pairing the  human  health, 
since 

1.  There  are  known 
cases  in  which  severe  dis- 
turbances  of  health   re- 
sulted from  the  ingestion 
of  such  milk. 

2.  The     investiga- 
tions of  streptococci 
scientifically  justify  the 

suspicion  of  harm  arising  from  their  ingestion. 

What  are  the  conditions  of  the  mastitis  streptococci  among 
themselves?  Formerly  a  Streptococcus  brevis  and  a  Streptococcus 
longus  were  distinguished,  but  it  was  shown  that  these  distinguish- 
ing features  were  not  absolute  (Staeheli).  The  differences  of  the  in- 
dividual strains  and  the  forms  of  their  growth  in  culture  are  as  in- 
constant as  their  pathogenicity,  acid  formation,  and  other  biological 
characteristics,  so  that,  as  expressed  by  Kitt,  it  would  be  necessary 
to  distinguish  as  many  varieties  as  there  are  mastitis  cases  if  it 
was  desired  to  accept  the  differences  of  the  individual  mastitis 
strains  as  indicative  of  different  varieties.  All  the  smaller  and 
greater  differences  should  be  considered  as  indications  of  adapta- 


Streptococcic  pus  from  milk  of  a  cow  with  streptococcic 
mastitis.      Streptococcus    longus.      1  X  1000. 


Effect  of  Internal  Influences. 


tion  to  the  various  energies  of  reaction  of  the  various  animals  and 
organs,  and  as  the  investigations  of  the  author  showed,  to  energy 
reaction  of  the  same  milk  gland  at  different  times.  For  instance  it 
appears  that  certain  changes  in  form  bear  a  definite  relation  to 
the  number  of  leucocytes  in  the  milk.  Thus  the  author  obtained 
the  following  results  in  the  same  quarter  of  a  cow  examined  at  dif- 
ferent times : 

L. — Leucocytes. 
Str. — Streptococci. 


Dec.  17 

,  1908. 

Jan. 

4,  1909. 

Cow  No.  29 

L. 

Str. 

L. 

Str. 

1  right  fore 

0.3 

0 

.1 

0 

2  left    fore 

0.2 

0 

0.9 

Dipl. 

3  right  hind 

500.0 

longus 

2.0 

brevis 

4  left    hind 

500.0 

longus 

20.0 

longus 

Cow  No.  34 

Dec.  : 

L7,  1908. 

Jan. 

5,  1900. 

1  right  fore 

0.1 

0 

0.2 

0 

2  left    fore 

0.2 

Dipl. 

Drops 

3  right  hind 

0.4 

Dipl. 

0.3 

Dipl. 

4  left    hind 

0.3 

Dipl. 

0.5 

brevis 

Dec. 

18,  1908. 

Cow  No.  31 

L. 

Str. 

1  right   fore 

0.5 

Dipl. 

2  left  fore 

1.5 

0 

3  right  hind 

1.2 

Dipl. 

4  left  hind 

1.3 

brevis 

Cow  No.  33 

1  right"  fore 

2  0 

brevis 

2  left  fore 

0.5 

0 

3  right  hind 

1.3 

brevis 

4  left  hind 

0.9 

brevis 

Cow  No.  58 

Dec.  : 

19,  1908. 

1  right   fore 

0.1 

0 

2  left  fore 

0.4 

brevis 

3  right  hind 

0.3 

0 

4  left  hind 

0.1 

0 

Jan.  20,  1909. 
L.  Str. 

0.5  0 

0.4          brevis 
1.9          brevis 


Jan.  25,  1909. 
L.  Str 

0.2  0 

2.0         brevis 
3.0         brevis 


0.5 


brevis       10.0          longus 


Jan 
0.1 
0.3 
3.0 
4.0 

.  16,  1909       Jan.  29.  1909. 
0             0.2            0 
0             0.5            0 
longus     50.9          brevis 
longus     60.0          brevis 

Jan.  4,  1909. 
L.      Str. 
0.3                      brevis 
200.0               medium  sized 
1.8                      brevis 
0.9                       Dipl. 

0.3                       Dipl. 
0.2                           0 
20.0                      longus 
10.0                      longus 

Jan.  5,  1909. 
0.5  Dipl. 

0.3  Dipl. 

0.1  0 

0.1  0 

These  differences  in  the  forms  of  streptococci  may  be  seen  dur- 
ing one  milking  on  the  same  animal,  if  they  are  compared  at  the 
beginning,  the  middle  and  at  the  conclusion  of  the  milking.  These 
differences  are  only  slight,  so  that  no  definite  conclusions  should  be 
drawn  from  them. 

If  however  the  results  from  various  animals  are  compared  it 
may  be  seen,  as  already  indicated  above,  that  certain  relations  exist 
between  the  number  of  leucocytes  and  the  forms  of  the  streptococci 
since  the  streptococci  become  longer  as  the  number  of  leucocytes 
increases.  The  experiments  extended  from  December  11,  1908,  to 
February  8,  1909,  and  include  three  stables  with  a  total  of  149 
cows. 

Of  these  149  cows  59,  or  39.6%  were  more  or  less  affected.  In 
most  animals  (140),  all  quarters  were  separately  examined  and 


Streptococcie  Mastitis.  95 


showed  that  out  of  560  quarters  112,  or  20%  were  affected.  Forty- 
two  of  these  gave  at  times  a  greater,  at  other  times  a  smaller  secre- 
tion with  a  distinctly  changed  consistency.  The  other  70  manifested 
the  infection  only  after  sedimentation,  or  only  through  microscopi- 
cal examination.  Some  of  these  12  quarters  were  successively  (see 
above)  examined,  so  that  the  material  used  for  smears  from  af- 
fected quarters,  and  which  had  been  microscopically  examined, 
amounted  during  the  period  mentioned,  to  134. 

Fifty-five  affected  quarters  showed  the  Streptococcus  brevis, 
32  the  Streptococcus  longus;  in  47  the  infective  agent  was  recog- 
nized in  the  form  of  a  diplococcus.  The  47  quarters  with  diplococci 
had  as  a  rule  a  very  small  leucocytic  number.  In  values  of  over 
2.0,  longer  coccus-chains  were  always  observed. 

32  quarters  out  of  the  47  had  0 . 5 :1000  leucocytes 

12  quarters  out  of  the  47  had  1.0:1000  leucocytes 
3  quarters  out  of  the  47  had  2 . 0 :1000  leucocytes 
In  the  55  cases  with  Streptococcus  brevis  the  change  in  the 
leucocytic  number  varied  to  a  greater  extent. 

In  18  it  represented  0.5:1000  or  32.73%. 

In  14  it  represented  1.0:1000  or  25.47%. 

In    8  it  represented  2.0:1000  or  14.55%. 

In     3  it  represented  over  2.0:1000  or  5.45%. 

In  12  it  represented  5-20  and  more  :1000  or  21.82%. 
The  32  longus-cases  were  divided  as  follows : 

Leucocytic  Quantity.  Number  of  Cases.       Percentage. 

Under  0.5:1000  1  3.125 

up  to    1.0:1000  1  3.125 

up  to     2.0:1000  3  9.375 

up  to   5.0:1000  3  9.375 

up  to  20.0:1000  3  9.375 

up  to  100  and  more:1000  21  65.625 

In  other  words : 

In  leucocytic  quantities 

Up  to    0.5,  63.00%  showed 35.0%  brevis,     2.00%  Dipl.  longus 

Up  to     1.0,  44.40%  showed 51.9%  brevis,    3.70%  Dipl.  longus 

Up  to    2.0,  17.65%  showed 64.7%  brevis,  17.64%  Dipl.  longug 

Up  to    5.0,    0.00%  showed 50.0%  brevis,  50.00%  Dipl.  longus 

Up  to  20.0,  and  more  0.00%  showed 33.0%  brevis,  66.60%  Dipl.  longus 

The  leucocytic  values  will  be  taken  up  again  later  in  the  dis- 
cussion of  the  "Trommsdorff"  test. 

From  this  tabulation  it  may  be  seen  that  the  length  of  the 
chains  actually  grows  with  the  increase  of  leucocytes,  or  with  the 
amount  of  sediment.  In  high  leucocytic  values  and  short  forms 
of  the  infective  agents,  the  latter  are  frequently  present  in  exceed- 
ingly large  qantities. 

*The  opinion  that  the  form  of  the  streptococcus  represents  an 
adaptation  to  the  energy  reaction  of  the  respective  animal  and  or- 
gan is  thereby  substantiated  especially  when  the  streptococci  are 


96  Effect  of  Internal  Influences. 

found  in  the  secretion  of  one  and  the  same  part  of  the  udder  of  a 
cow  at  different  times. 

In  the  same  way  it  is  impossible  to  establish  rules  for  definite 
differentiation  of  the  streptococci  of  the  yellow  garget  among  them- 
selves through  the  study  of  their  morphological  relations,  by  com- 
parison of  their  biochemic  characteristics  or  the  pathogenic  viru- 
lence of  individual  strains,  since  the  acid  production  and 
acid  susceptibility  which  are  present  in  mastitis  streptococci  at  first 
may  be  easily  changed  by  artificial  means,  and  individual  strains 
have  proven  the  possession  of  stronger,  others  a  weaker  pathogenic 
action  for  test  animals  (Groning,  Sven  Wall). 

The  author  does  not  desire  by  any  means  to  establish  a  theory 
of  unity  for  mastitis  streptococci.  To  be  sure  there  are  marked 
differences  in  the  various  strains,  especially  in  regard  to  the  pro- 
duction of  clinical  symptoms,  which  cannot  be  attributed  alone  to 
the  variation  of  virulence,  and  to  unequal  resisting  powers. 

It  is  possible  that  with  the  aid  of  newer  methods  of  differ- 
entiation (blood  media,  etc.)  it  will  be  possible  to  establish  a  fun- 
damental type  of  mastitis  streptococci  in  strains  freshly  cultivated 
from  animals.  Even  if  with  the  continuance  of  cultivation  new 
characteristics,  as  for  instance  hemolytic  properties,  may  be 
acquired  by  the  cultures,  and  the  earlier  characteristics  become  lost, 
the  characteristics  acquired  by  the  respective  strains  of  streptococci 
in  their  former  growth  may  remain  constant  for  a  sufficient  length 
of  time  to  permit  the  establishment  of  the  type  of  varieties,  as  has 
already  been  the  case  with  the  streptococci  of  man  (Petruschky, 
Schottmiiller,  Baumann,  Schulze  and  others).  Enrst,  Gminder  and 
others  have  demonstrated  that  the  mastitis  streptococci  mostly 
correspond  to  the  mitior  seu  viridans  or  mucosus  horn,  group, 
respectively. 

Based  on  the  grounds  previously  described,  milk  hygienists, 
bacteriologists,  children  specialists  and  veterinarians  sometimes 
more  and  at  other  times  less  imperatively  have  demanded  the  ex- 
clusion of  cows  with  streptococcic  mastitis  from  the  production  of 
milk  (Jensen,  Weigmann,  Blevel,  Sven  Wall,  Ruhm,  Trommsdorff, 
Seiffert,  Ernst  and  others). 

This  requirement  is  natural  from  the  hygienic  standpoint,  but 
its  practical  execution  is  rendered  very  difficult  by  the  remarkable 
prevalence  of  the  disease,  and  as  a  matter  of  fact  as  long  as  the 
general  control  of  production  and  the  examination  of  milk  of  indivi- 
dual cows  are  not  required  a  thorough  enforcement  cannot  be 
hoped  for. 

For  the  present  the  exclusion  from  the  market  of  all  milk  which 
shows  changes  in  a  recognizable  way,  as  for  instance  through  a 
collection  of  yellow  sediment,  should  be  considered  satisfactory.  At 
the  same  time  from  an  economic  standpoint  only  milk  from  affected 
quarters  should  be  excluded,  while  the  sale  of  milk  from  healthy 
quarters  should  be  allowed. 


Udder  Tuberculosis. 


97 


TUBERCULOSIS. 

Occurrence  of  Tuberculosis  in  Cattle. 

Tuberculosis  of  the  udder  in  cows  appears  with  relative  fre- 
quency, corresponding  to  the  frequent  occurrence  of  tuberculosis 
in  cattle. 

Tuberculosis  in  the  udder  is  manifested  in  different  forms, 
the  circumscribed,  lobular,  focal  tuberculosis  and  the  diffuse  tuber- 
Fit?.  22. 


Tuberculosis  of  the  udder.     Progressive  miliary  form. 

culosis  extending  over  and  infiltrating  the  entire  udder.  Two  of 
the  different  forms  may  be  present  at  the  same  time  in  the  organ, 
and  from  one  form  through  accentuation  of  the  infection  the  other 
forms  may  result. 

Clinically  tuberculosis  is  manifested  by  nodular  swelling  or 
hard  enlargement  of  the  affected  quarter,  and  with  enlargement  and 
painless  nodular  swelling  of  the  supramammary  lymph  glands. 
These  changes,  however  develop  very  slowly  and  the  milk  from  such 
infected  quarters  for  weeks  and  months  may  contain  millions  of 


98  Tuberculosis. 


tubercle  bacilli  without  the  udder  indicating  any  special  lesions, 
and  without  the  milk  showing  any  noteworthy  changes. 

The  quantity  of  the  secretion  from  a  tuberculous  quarter  is  at 
first  uninfluenced,  or  only  slightly  so ;  later  it  is  considerably  dimin- 
ished. For  a  long  time*  it  is  of  a  normal  appearance ;  later  it 
generally  becomes  thick,  transparent,  watery,  intermixed  with  small 
flakes,  or  again  it  may  become  thick,  yellow,  pus-like,  depending  on 
the  intensity  and  extension  of  the  lesions  in  the  udder  and  the  in- 
fluence of  the  general  health  of  the  cow. 

Tuberculosis  of  the  udder  as  a  rule  is  of  an  embolic  character, 
and  rarely  represents  the  result  of  a  galactiferous  infection.  No- 
card,  Meyer,  Calmette  and  Guerin,  and  Zwick  succeeded  in  pro- 
ducing tuberculosis  of  the  udder  of  various  characters,  by  injections 
of  bovine  and  human  tubercle  bacilli  into  the  milk  duct  of  the  teats. 
The  pathologico-anatomical  appearance  in  these  instances  was  the 
same. 

The  extent  of  the  spread  of  tuberculosis  in  cattle  in  general  is 
best  indicated  by  the  statistics  of  abattoirs  in  the  different  states. 

In  Germany  in  1904, 17.89%,  in  1905, 19.16%,  in  1906,  20.66%, 
and  in  1907,  21.21%  of  cattle  were  retained  on  account  of  tuber- 
culosis, and  0.26%,  0.30%,  and  0.35%,  respectively,  on  account  of 
tuberculosis  of  the  udder.  In  Bavaria  in  1898,  5.7%  ;  1900,  6.0%  ; 
1902,  6.8%;  1904,  9.2%;  1906,  10.31%,  were  tuberculous. 

The  spread  of  tuberculosis  is  especially  assisted  by  exposure 
in  stabling  (in  1907,  7.28%  of  young  stock,  18.54%  bulls,  22.55% 
steers,  and  29.62%  of  cows  were  found  to  be  tuberculous  on 
slaughter,  against  5.3%,  13.9%,  18.3%  and  25.3%,  respectively, 
in  1904),  and  forced  feeding  while  the  percentage  in  pasture  ani- 
mals diminishes  considerably,  and  in  range  cattle  tuberculosis  is 
practically  unknown.  In  Prussia  the  total  infection  from  1898  to 
1906  is  estimated  at  16.09  to  23.4%,  in  Saxony  from  30.46  to  37.58%, 
from  1898  to  1908.  In  France  in  certain  localities  the  infection  ex- 
ists in  30  to  40%  of  the  stock,  an  average  of  10%.  In  other 
countries  similar  conditions  obtain. 

If  the  abattoir  findings  are  not  considered  as  indicative  of  real 
conditions,  and  delicate  biological  methods  are  employed  which 
prove  that  an  animal  is  infected  with  the  tubercle  bacillus  (with- 
out however  manifesting  anatomically  demonstrable  changes)  the 
increase  of  the  numbers  is  considerable. 

In  Saxony  from  1891  to  1897,  in  round  numbers  two-thirds  of 
the  cattle  were  found  to  be  infected  through  the  aid  of  tuberculin. 
Ostertag  accepts  25%  of  the  cattle  as  infected  in  northern  Germany 
and  around  Stuttgart,  basing  his  estimate  on  sample  testing  in  the 
various  localities.  In  France  from  50-80%  of  the  animals  reacted, 
in  Great  Britain  27%,  in  Austria  14-60%,  in  Hungary  up  to  35 . 18%, 
Belguim  48.8%,  Norway  22.8%,  Sweden  about  31%,  Finland 
13.7%.  In  Denmark  during  the  first  years  of  the  tuberculosis 
eradication  38.5  to  40%  of  the  animals  gave  tuberculin  reactions, 
while  later  only  8.5%  reacted. 


Frequency  of  Tuberculosis.  99 


[The  extent  of  tuberculous  infection  among  cattle  in  the  United 
States  is  indicated  by  the  statistical  reports  of  the  Federal  Bureau 
of  Animal  Industry.  According  to  these  figures  out  of  400,000 
cattle  tested,  there  were  37,000  reactors  or  9.25%.  The  majority 
of  these  animals  were  dairy  cattle,  from  which  fact  the  conclusion 
has  been  drawn  that  approximately  10%  of  the  dairy  cattle  in  this 
country  are  affected  with  tuberculosis.  On  the  other  hand  the  meat 
inspection  statistics  show  that  6,978,293  cattle  were  slaughtered  in 
official  establishments  during  1913,  of  which  75,870  were  found 
tuberculous,  suggesting  that  probably  1%  of  beef  cattle  are  affected 
with  tuberculosis  to  some  degree. — Trans.] 

The  relative  frequency  of  tuberculosis  of  the  udder  corres- 
ponds to  the  numerous  occurrences  of  bovine  tuberculosis. 

According  to  Bergmann  3.5%  of  the  tuberculous  cows  slaugh- 
tered at  Malmo  were  also  affected  with  tuberculosis  of  the  udder. 
Ostertag  estimates  the  appearance  of  tuberculosis  of  the  udder  in 
0.1  to  0.3%  for  Germany.  These  figures  of  course  increase  in  lo- 
calities in  which  the  other  forms  of  tuberculosis  occur  with  greater 
frequency.  Thus  Meyer-Stendal  report  that  out  of  818  cows  4% 
showed  udder  tuberculosis.  Meissner  found  in  1910  from  all  cows 
examined  in  Posen  0.32%  affected  with  udder  tuberculosis. 

Bugge  mentions  out  of  16,050  cows  included  in  the  eradication 
work  at  Schleswig-Holstein  in  1906,  the  presence  of  tubercle  bacilli 
in  30  out  of  318  examinations  of  mixed  milk,  and  in  27  out  of  562 
individual  milk  tests  of  suspected  cows. 

In  1907  the  tests  for  tuberculosis  of  258  samples  of  mixed 
milk,  revealed  tubercle  bacilli  in  35  while  out  of  597  individual  milk 
samples,  tubercle  bacilli  were  found  in  32,  which  corresponds  to 
0.14%  of  open  udder  tuberculosis  in  the  23,278  examined  animals 
(pulmonary  tuberculosis  5.1%). 

In  1908  these  numbers  amounted  to  0.124  to  2.644%  respec- 
tively out  of  38,454  animals. 

In  the  presence  of  such  an  extension  it  should  be  not  at  all 
surprising  that  market  milk  contains  tubercle  bacilli  with  extraor- 
dinary frequency.  Examinations  for  this  purpose  were  under- 
taken as  early  as  1893  by  Montefusko  in  Naples,  in  1894  by  F'riis 
in  Copenhagen,  in  1895  by  Obermuller  and  Fiorentini,  in  1898  by 
Petri,  1900  by  Beck  in  Berlin,  in  1895  by  Zacharbeko  in  Petersburg, 
1897  by  Massone  in  Genoa,  Buege  in  Halle,  Boyce  and  Delepine  in 
Liverpool,  Klein  in  London,  Nonewitsch  in  Wilna,  Stepanow  in 
Kasan,  Bujwid  in  Krakau,  and  in  1905  to  1906  by  Eber  in  Leipzig, 
with  varying  results. 

The  numbers  of  tubercular  infection  of  market  milk  obtained 
(other  investigators  for  instance  Brusaferro,  Roth,  Schuchardt, 
Groning,  Petri,  Eabinowitsch,  Hermann  and  Morgenroth,  Ascher, 
Coggi,  Bonhoff,  Herbert,  Markl,  Herr  and  Beninde,  Eber  and  others 
experimented  with  butter  and  cheese)  fluctuated  between  0  and 
100%. 


100  Tuberculosis. 


It  is  to  be  expected  that  all  market  milk,  no  matter  of  what 
origin,  may  occasionally  be  infected  with  tubercle  bacilli ;  all  milk 
in  the  production  of  which  no  special  care  is  taken  in  the  selection  of 
the  milking  animals  and  no  clinical  examination  or  tuberculinization 
of  the  animals  has  been  undertaken,  should  be  suspected  of  contain- 
ing tubercle  bacilli,  and  the  larger  the  herd  which  produces  the 
milk,  the  greater  the  danger. 

German  investigators  established  the  following  figures  for  the 
presence  of  tubercle  bacilli  in  market  milk : 

Author.  Samples.       Place.  Tubercular  %. 

Obermuller    13  Berlin   61 

Buege   6  Halle  33 . 3 

Petri   64  Berlin   14 

Beck    56  Berlin   30.3 

Proskauer    9  Market  milk  Berlin 55.5 

Seeligmann    5  Dairies  under  veterinary  control  . .     0. 

Croner    13  Danish  milk .' 38.5 

Eber    210  Leipzig   10.5 

[The  percentage  of  tubercle  bacilli  found  in  the  milk  supply 
of  large  cities  in  this  country  has  been  accurately  determined  in 
only  a  few  instances.  In  1907  Anderson  proved  that  in  Washing- 
ton, D.  C.,  10.7%  of  the  dairies  supplied  milk  containing  virulent 
tubercle  bacilli,  Schroeder  found  7.7%  of  the  26  dairies  examined 
were  distributing  infected  milk  to  Washington,  D.  C.,  while  still 
later  Mohler  showed  that  about  3%  of  the  73  samples  of  milk  ex- 
amined contained  tubercle  bacilli.  The  apparent  discrepancy  in 
these  results  may  be  readily  explained  by  the  fact  that  during  the 
last  6  years  strenuous  efforts  have  been  carried  on  by  the  Bureau  of 
Animal  Industry  to  eradicate  tuberculosis  from  among  these  herds, 
with  the  result  that  in  the  District  of  Columbia  the  number  of 
tuberculous  animals  has  been  reduced  from  18.8%  to  1.2%  in 
1914.  Hess  has  found  that  17,  or  16%,  of  107  samples  of  milk  dis- 
tributed in  New  York  City  contained  virulent  tubercle  bacilli, 
while  Campbell  made  extensive  investigations  of  the  occurrence 
of  tubercle  bacilli  in  the  market  milk  of  Philadelphia,  and  found 
18  or  13 . 8%  of  the  130  samples  examined  to  contain  living  bacilli  of 
tuberculosis. — Trans.] 

Under  What  Conditions  Do  Tubercle  Bacilli 
Enter  the  Milk? 

The  infection  with  tubercle  bacilli  is  natural  when  the  animal 
is  affected  with  tuberculosis  of  the  udder,  or  may  occur  indirectly 
when  through  contamination  of  the  udder  with  feces  in  pulmonary 
or  intestinal  tuberculosis,  urine  or  vaginal  secretion  in  kidney  or 
uterine  tuberculosis,  or  with  infected  straw,  tubercle  bacilli  are 
brushed  off  from  the  soiled  udder  into  the  drawn  milk,  or  when  in 


Infectiousness  of  ?l\tilkV-»  '     i  *'  \, >''/>  I  '••]  \  /       101 


open  tuberculosis  of  the  lungs  the  bacteria  get  into  the  milk  through 
the  air  or  straw. 

As  early  as  1869,  prior  to  the  discovery  of  the  tubercle  bacil- 
lus by  Koch  in  1882,  Gerlach  proved  the  infectiousness  of  milk 
from  highly  tuberculous  animals  through  feeding  and  inoculation 
experiments.  This  was  also  emphasized  by  Ziirn,  Klebs,  Sommer, 
and  in  1880  by  Bellinger,  who  first  pointed  to  the  fact  that  the  milk 
of  a  tuberculous  cow  in  which  the  udder  is  not  noticeably  affected 
may  contain  tubercle  bacilli.  The  same  results  are  shown  by  the 
works  of  Stein,  Bang,  Hirschberger,  Ernst,  Schroeder  and  Fiorenti, 
who  succeeded  in  producing  tuberculosis  in  test  animals  with  milk 
of  tuberculous  cattle,  even  though  there  was  no  udder  tuberculosis 
present.  Milk  from  tuberculous  udders  always  has  been  proved 
to  be  especially  dangerous  (May,  Bang). 

If  special  care  were  exercised  in  milking,  it  not  infrequently 
happens  even  in  extensive,  generalized  tuberculosis  that  the  in- 
oculated animals  remain  well ;  thus  Nocard  from  injecting  milk  of 
54  cows  affected  with  generalized  tuberculosis  succeeded  only  in 
3  cases  in  producing  inoculation  tuberculosis.  Therefore  it  ap- 
pears that  in  spite  of  a  generalized  tuberculosis  when  udder  tuber- 
culosis is  not  present,  tubercle  bacilli  are  not  always  excreted 
with  the  milk ;  the  possibility  of  elimination  however,  that  is,  that 
the  milk  of  such  a  tuberculous  cow  may  contain  tubercle  bacilli, 
should  at  all  times  be  given  consideration. 

Is  milk  liable  to  be  affected  when  tuberculosis  cannot  be  clin- 
ically demonstrated  in  suspected  cows,  or  wrhen  they  appear  healthy 
and  yet  react  to  tuberculin?  Are  tubercle  bacilli  eliminated  only 
with  the  milk  from  animals  affected  with  tuberculosis  of  the  udder, 
or  also  in  cases  where  the  udder  is  not  affected  by  tuberculosis? 
These  questions  may  be  answered  at  the  present  time  with  great 
certainty,  namely,  that  tubercle  bacilli  of  cattle  are  eliminated  with 
the  milk  as  a  rule  only  in  animals  which  are  affected  with  tubercular 
mastitis.  This  question  is  of  especial  interest  in  the  eradication  of 
tuberculosis  in  the  dairy  herd,  since  it  is  well  known  that  calves  and 
hogs  are  highly  susceptible  to  the  tubercle  bacillus  of  cattle.  It 
will  be  advisable  therefore  to  refer  to  the  more  important  publica- 
tions on  the  elimination  of  tubercle  bacilli  with  the  milk,  before 
entering  into  the  question  of  the  harmfulness  of  such  for  man. 

Delepine,  Ravenel,  Rabinowitsch  and  Kempner,  Gehrmann,  Gehrmann  and 
Evans,  Moussu  and  Mohler  obtained  positive  results  from  milk  of  animals  not  clini- 
cally affected,  but  reacting  to  the  tuberculin  test,  through  inoculating  or  feeding  of  test 
animals. 

Other  investigators,  as  Martel  and  Guerin,  also  Hirschberger,  aimed  to  solve  the 
question  by  inoculating  the  milk  of  slaughtered  animals  or  glandular  substance  from 
udders  of  reacting  animals.  Their  work  also  frequently  gave  positive  results.  All  of 
these  authors  therefore,  conclude  with  great  certainty  that  tubercle  "bacilli  may  "be 
eliminated  with  the  milk  even  from  animals  which  are  not  clinically  affected  with  tu- 
berculosis. 

Other  views  are  supported  by  Archer,  Muller,  Ostertag,  Stenstrom,  McWeeney, 
Pusch  and  Hessler  as  the  result  of  their  negative  findings,  namely,  if  the  experiments 
were  conducted  under  the  most  painstaking  requirements  and  all  contaminations  through 


102     '  '  '  tuberculosis. 


infected  straw,  etc.,  were  avoided  as  much  as  possible,  they  failed  in  spite  of  numerous 
experiments  in  producing  tuberculosis  with  milk  from  a  tuberculin  reacting  animal,  and 
frequently  not  even  with  the  milk  from  an  animal  clinically  affected,  but  free  from 
tuberculosis  of  the  udder. 

From  the  standpoint  of  milk  hygiene  the  fact  is  important  that 
in  the  work  of  tuberculosis  eradication  by  the  agricultural  societies 
the  examinations  for  tubercle  bacilli  in  the  mixed  milk  of  individ- 
ual herds  were  mostly  negative  after  the  clinically  affected  tuber- 
cular animals  had  been  eliminated.  According  to  the  works  of 
Muller  and  Hessler  until  July  1907,  2,949  samples  of  mixed  milk 
of  individual  herds  were  examined;  all  of  these  herds  were  sub- 
jected to  the  Siedamgrotzky-Ostertag  method  of  eradication.  From 
30  to  200  cows  participated  in  each  test  and  156  herds  gave  milk 
free  of  tubercle  bacilli.  As  eliminators  of  tubercle  bacilli  were 
found : 

Two  cows  with  udder  tuberculosis,  8  times  each. 

One  or  more  COWTS  with  tuberculosis  of  the  uterus,  16  times. 

One  or  more  cows  with  tuberculosis  of  the  uterus,  6  times. 

Once  kidney  and  uterine  tuberculosis. 

Once  pulmonary  and  intestinal  tuberculosis. 

Once  a  cow  whose  saliva  contained  tubercle  bacilli  and 

19  times  open  pulmonary  tuberculosis. 

In  five  positive  tests  there  was  no  clinically  demonstrable  form 
of  tuberculosis,  and  the  subsequent  tests  of  immediately  drawn  con- 
trol samples  remained  negative.  These  five  cases  wrere  observed  in 
the  beginning  of  the  eradication  work. 

The  remaining  2,793  milk  samples  were  free  of  tuberculosis  in 
spite  of  the  fact  that  among  the  animals  of  these  herds  there  were 
surely  a  great  number  which  would  have  positively  reacted  to 
tuberculin  tests. 

The  five  cafes  observed  at  the  beginning  of  the  eradication  work,  in  which  the 
milk  contained  tubercle  bacilli,  although  clinically  open  cases  of  tuberculosis  could  not 
be  found  on  stable  examination,  are  explained  by  Hessler  in  that  the  milk  became  contami- 
nated with  particles  of  the  feces  from  pulmonary  cases  of  tuberculosis,  which  had  not  yet 
developed  clinically.  This  is  also  suggested  by  the  smaller  number  of  bacilli  found  in  the 
milk. 

Tubercle  bacilli  therefore  occur  in  the  milk  in  great  numbers 
when  animals  with  open  tuberculosis,  and  tuberculosis  of  the  udder 
stand  in  the  stable.  Milk  from  animals  which  manifest  their  tuber- 
culosis by  a  positive  tuberculin  reaction,  will  usually  be  free  from 
tubercle  bacilli.  Such  cows  belong  to  the  least  dangerous  class. 
Nevertheless  the  investigations  of  Rabinowitsch,  Kempner,  Rav- 
enel  and  others,  who  obtained  positive  inoculation  results  with  milk 
from  reacting  animals,  prove  that  such  milk  may  at  times  contain 
tubercle  bacilli  in  small  numbers.  Ordinarily  however  this  will 
not  be  the  case,  and  the  milk  of  such  animals  may,  as  a  whole, 
be  considered  free  from  tubercle  bacilli. 

Therefore  it  appears  evident  that  under  present  conditions  of 
milk  production  the  ingestion  of  tubercle  bacilli  with  milk  is  possi- 
ble at  almost  all  times. 


Tubercle  Bacilli  Types. 


103 


What  Danger  Threatens  Man  Through  Ingestion  of  Milk  Which 
Contains  Bovine  Tubercle  Bacilli? 

In  order  to  answer  this  question  it  is  necessary  to  refer 
to  the  development  of  tuberculosis  in  man,  and  to  consider  the  fac- 
tors which  are  necessary  for  an  infection  of  his  body. 

These  factors  in  addition  to  the  toxicity  of  the  infective  agent, 
and  the  quantity  in  which  it  has  the  opportunity  to  enter  the  body, 
depend  upon  the  avenues  of  infection  which  it  takes  and  the  local 
and  general  resistance  of  the  attacked  individuals  towards  the  spe- 
cific infective  agent. 

There  is  perfect  agreement  relative  to  the  virulence  of  the 
bovine  tubercle  bacillus  for  man.  The  bovine  tubercle  bacillus  is  a 
strain  of  the  tubercle  bacillus  with  such  pregnant  characteristics 
that  it  is  almost  invariably  possible  to  classify  it  separately  from 
other  strains  when  obtained  in  culture,  that  is,  to  distinguish  the 
bovine  tubercle  bacillus  from  the  bacillus  of  the  human  type. 

These  bacilli  are  distinguished  as  the  typus  bovinus  and 
typus  humanus  (only  these  two  types  need  to  be  considered  from 
the  standpoint  of  milk  hygiene)  which  are  characterized  by  the  fol- 
lowing peculiarities : 


Typ.  Bovinus. 

The  growth  is  delicate  and 
in  the  thin  film  small  wart-like 
colonies  develop;  on  bouillon  a 
mesh-like  fine  membrane  with 
wart-like  prominences  develops 
proliferating  downward,  or  a 
membrane  of  tissue-paper  thick- 
ness results;  the  bouillon  is 
probably  neutralized  and  finally 
becomes  alkaline. 

The  bovine  tubercle  bacil- 
lus is  as  a  rule  of  greater 
toxicity  for  smaller  mammalia. 
Rabbits  develop  through  intra- 
venous injections  of  the  bacillus 
(0.001  gm.),  a  generalized  tu- 
berculosis from  which  the  ani- 
mals succumb  inside  of  three 
weeks.  When  0.01  gm.  is  in- 
jected under  the  abdominal  skin, 
it  produces  in  a  short  time,  gen- 
eralized tuberculosis. 

Cattle   succumb  readily  to 


Typ.  Humanus. 

The  growth  is  a  luxuriant, 
uniformly  thick  and  wrinkled 
membrane,  which  proliferates 
on  the  wall  of  the  tube.  The 
growth  is  the  same  in  bouillon; 
the  degree  of  acidity  of  the 
bouillon  is  usually  at  first 
diminished,  later  increased. 

0.001  gm.  of  bacilli  of  the 
human  type  intravenously  in- 
jected produces  after  months 
only  a  chronic  form  of  tuberculo- 
sis (joints,  kidneys,  lungs, 
testicles). 

The  injection  under  the  ab- 
dominal wall  produces  only  local 
lesions. 

Inoculated  into  cattle  the 
bacilli  of  the  human  type  (0.05 
gm.  subcutaneously),  produce 
only  slight  or  no  pathogenic  ac- 
tion. The  process  remains 
local,  and  extends  only  to  the 


104 


Tuberculosis, 


infection  with  the  typus  bovin- 
us,  from  an  extensive  form  of 
tuberculosis.  Guinea  pigs  die 
more  quickly  from  an  inocula- 
tion with  bovine  tubercle  bacilli 
than  from  an  inoculation  with 
the  bacillus  of  human  type. 


neighboring    glands;    a    great 
healing  tendency  prevails. 

Intravenous  injections  of  1 
mg.  of  the  typus  humanus  into 
the  vein  of  a  mouse  will  show  it 
to  possess  a  greater  resistance 
than  when  inoculated  with  the 
typus  bovinus. 

In  the  last  10  years  about  2000  strains  of  tubercle  bacilli  from  man  and  cattle 
have  been  cultivated  and  studied.  In  these  studies  even  further  differences  were  found 
which,  however,  are  not  as  constant  as  those  given  above;  for  instance,  the  bacillus  of 
the  human  type  in  glycerin  bouillon  cultures  is  delicate,  slender,  slightly  curved,  and 
of  beaded  staining  qualities,  whereas  the  bovine  strain  is  regular,  plump,  thick  without 
granular  differentiation  in  staining,  and  frequently  with  swollen  ends.  The  pigment 
formation  on  glycerin  potato  is  more  typical  of  the  human  type  than  the  bovine  type. 
The  former  when  placed  on  serum  in  hermetically  sealed  glass  tubes  remains  viable  for 
twelve  months,  the  latter  for  over  a  year. 

Contrary  to  the  views  of  many  investigators  of  tuberculosis, 
Nocard,  Hueppe,  Von  Behring,  Komer,  de  Jong  and  others  support 
the  theory  that  the  tubercle  bacillus  adapts  itself  to  the  infected 
animal  and  becomes  transformed  as  a  result  of  its  environment. 
Rabinowitsch,  Dammann  and  Eber  have  also  supported  this  trans- 
formation theory.  The  latter  especially  attempted  to  prove  by  ex- 
tensive experiments  and  investigations  that  Bacillus  humanus, 
by  passage  through  cattle,  changes  into  the  bovine  type.  This 
question  however  appears  at  the  present,  to  be  decided  in  favor 
of  the  stability  of  the  bacillus. 

It  has  at  least  been  shown  with  six  various  strains  of  the  human  type,  that  in 
passage  experiments  through  2  to  7  cattle,  in  from  247  to  512  days,  the  character  of 
the  bacillus  was  not  changed  (English  Commission  and  Weber),  and  that  bacilli  of 
the  human  type  by  eight  subsequent  passages  through  goats,  in  516  days,  and  by  four 
passages  through  cattle  in  685  days,  were  not  influenced  in  their  typical  characteristics. 

The  immunization  experiments  which  were  undertaken  with  the  bacillus  of  the 
human  type  on  cattle  showed  no  changes  whatsoever  in  the  human  type  after  the  pres- 
ence of  the  bacteria  in  cattle  for  a  year  and  seven  months  (Baldwin)  in  spite  of  their 
propagation  in  the  udder  of  the  cow.  The  same  results  were  obtained  in  three  experi- 
ments by  Weber,  Titze  and  Joern,  who  allowed  the  bacillus  of  the  human  type  to  exist 
in  the  body  of  cattle  for  two  years  and  one  month  and  for  two  years  and  six  months. 

Eber's  experiments  found  no  confirmation  in  the  Imperial  Board  of  Health;  the 
experiments  however  are  being  continued  in  strict  co-operation  with  Eber. 

On  the  contrary  it  is  shown  that  the  bovine  bacillus  constantly 
retains  its  characteristics  within  the  human  body. 

From  a  boy  who  was  affected  since  his  second  year  with  tuberculosis  of  the  fourth 
digital  bone  of  his  hand,  it  was  possible  during  surgical  interference  to  obtain  material 
from  the  same  place  at  five  different  times,  during  his  age  from  8  to  13  years.  The  in- 
fection was  caused  by  the  bovine  bacillus. 

In  spite  of  their  existence  for  ten  and  a  half  years  in  the  human  body  these 
bovine  bacilli  had  retained  their  characteristics.  A  marked  influence  in  their  virulence 
was  manifested,  however,  since  the  bacilli,  from  the  second  operation,  in  quantities  of 
2  mg.  could  no  longer  kill  rabbits  even  after  intravenous  inoculations.  From  the  sub- 
sequent operations  it  was  found  that  the  virulence  was  again  increased. 

Griffith  obtained  the  same  results  with  bovine  cultures  from  lupus  from  which  the 
bacilli  were  isolated  six  months,  two  and  three  and  a  half  years,  respectively,  after  the 
first  examination.  It  is  true  that  the  virulence  was  several  times  lower  than  is  or- 
dinarily the  case  with  the  bovine  type;  the  other  characteristics  of  the  strain  however 


Transmission  of  Bovine  Tuberculosis.  105 

were  tenaciously  retained.  In  one  of  the  cases  the  bacillus  persisted  in  the  human  body  for 
18 */2  years.  Passage  through  rabbits  and  cattle  again  increased  its  virulence.  Al- 
though through  animal  passage  a  change  of  the  virulence  is  possible,  nevertheless  this 
change  results  only  inside  of  the  borders  of  the  type  and  in  the  direction  of  the  type. 
The  bovine  bacillus  therefore  does  not  pass  into  the  human  type,  nor  the  latter 
bacillus  into  the  bovine  type. 

Only  a  brief  statement  will  be  made  relative  to  the  so-called 
atypical  strains.  It  has  been  demonstrated  that  there  are  cultural 
strains  which  cannot  be  classified  as  belonging  either  to  one  or  the 
other  type  (Kossel,  Weber  and  Heuss,  Lydia  Rabinowitsch,  de 
Jong  and  others).  These  strains  proved  to  be  mixed  cultures  of 
both  types.  In  the  same  person  not  only  mixed  infections  of  both 
types  may  exist  in  the  affected  organs,  but  also  a  double  infection 
may  occur  in  such  a  way  that  in  one  organ  the  Typus  humanus,  and 
in  the  other  organ  the  Typus  bovinus,  may  be  found  in  pure  culture 
(Weber,  Weber  and  Taute,  Griffith,  Park  and  Krumwiede, 
Steffenhagen). 

In  1901  Koch  explained  at  the  International  Tuberculosis 
Congress  at  London,  that  tuberculosis  of  man  is  produced  by  a 
tubercle  bacillus  which  differs  from  the  bovine  tubercle  bacillus, 
and  expressed  himself  as  opposed  to  the  general  prevailing  opin- 
ion of  that  time,  regarding  the  great  danger  of  the  cattle  tubercle 
bacillus  for  man,  and  as  believing  that  the  transmissibility  of 
bovine  tuberculosis  to  man  was  so  slight  compared  with  the  dan- 
ger which  threatens  man  from  tuberculous  human  beings,  that  its 
practical  importance  was  negligible. 

Although  Koch's  statement  cannot  stand  in  the  directness  of 
his  declaration,  nevertheless  at  the  present  time  it  is  generally 
accepted  from  the  above  mentioned  differential  characters,  that 
marked  differences  exist  between  the  bacillus  of  bovine  tubercu- 
losis and  that  of  man,  and  it  is  a  fruitless  work  to  dispute  whether 
they  are  differences  of  varieties  or  peculiarities  of  the  different 
strains,  which  lead  to  the  variations,  if  we  accept  the  fact  that  the 
differences  of  the  strains  are  obstinately  retained. 

The  results  are  of  especial  value  in  differentiating  the  two 
types  of  tubercle  bacilli.  In  association  with  Shiitz,  Koch  under- 
took some  experiments  to  establish  points  of  differentiation. 

Nineteen  calves  which  were  infected  intravenously,  subcu- 
taneously,  intraperitoneally,  by  inhalation  or  feeding  experiments 
with  the  Bacillus  humanus,  showed  no  manifestations  of  disease,  in- 
creased in  weight,  and  on  autopsy  conducted  several  months  after 
infection,  showed  only  caseous  purulent  changes  at  the  point  of 
inoculation.  On  the  other  hand,  after  the  inoculation  of  bovine 
tubercle  bacilli,  severe  febrile  symptoms  and  extensive  tubercu- 
losis, especially  of  the  lungs,  liver  and  spleen  resulted.  The  same 
results  were  obtained  from  the  experiments  of  Kossel,  Weber, 
Heuss.  Bacilli  of  the  human  type  were  retained  in  the  regional 
lymph  glands ;  the  changes  induced  by  them  gradually  retrogressed, 
whereas  infection  with  the  bovine  type  of  the  bacillus  led  to  a  pro- 


106  Tuberculosis. 


gressive  tuberculosis.  Inhalation  and  feeding  experiments  showed 
the  slight  virulence  of  the  human  tubercle  bacillus  for  cattle. 

In  the  experiments  of  Nocard,  Meyer,  Calmette  and  Guerin 
and  Zwick,  the  inoculation  of  tubercle  bacilli  of  bovine  origin  into 
the  milk  ducts  resulted  in  a  tuberculosis  of  the  udder  with  rapid 
emaciation  of  the  animal,  terminating  in  death ;  whereas  the  bacilli 
of  human  origin  produced  only  a  passing  inflammatory  irritation, 
and  an  interstitial  atrophy  of  the  udder.  Calves  which  nursed  on 
these  latter  infected  udders  remained  healthy  (Zwick  and  Maier), 
or  on  the  other  hand  (in  one  case  of  Zwick)  intestinal  tuberculosis, 
with  tuberculosis  of  the  mesenteric  lymph  glands,  developed.  At 
autopsy  undertaken  20  weeks  after  the  infection,  the  udder  of  the 
cow  showed  atrophy  with  miliary  tuberculosis,  without  however 
typical  tuberculous  changes  in  the  regional  lymph  glands. 

From  these  results  the  conclusion  may  be  drawn  that  tubercle 
bacilli  of  human  origin  are  only  very  slightly  dangerous  for  cat- 
tle. It  should  be  considered  however  that  occasionally  after  artifi- 
cial infections  the  bacilli  may  persist  in  the  infected  region,  with 
or  without  marked  local  or  at  times  even  generalized  changes. 
Calves  may  develop  intestinal  tuberculosis  or  tuberculosis  of  the 
mesenteric  lymph  glands  as  a  result  of  ingesting  a  large  amount  of 
tubercle  bacilli  of  the  human  type. 

Almost  the  same  relation  exists  in  man  towards  the  bacillus 
of  bovine  tuberculosis.  The  principal  dangers  threatening  man 
are  through  the  possibility  of  infection  from  affected  human  beings, 
and  less  so  to  the  possibility  of  infection  with  diseased  products  of 
animal  origin,  as  for  instance  milk.  The  possibility  of  tuberculosis 
infection  through  animal  products  is  presented  with  remarkable 
frequency,  as  may  be  seen  from  the  above  statements;  still  the 
rarity  of  infection  with  the  bovine  type  is  quite  striking. 

Hogs  which  become  readily  infected  with  the  bovine  type  are  very  frequently  af- 
fected by  the  ingestion  of  skimmed  milk  containing  tubercle  bacilli. 

In  northern  Germany  some  of  the  herds  show  an  infection  of  50-60,  occasionally 
even  up  to  90%.  The  experience  at  the  tuberculosis  eradication  stations  indicated  that 
by  the  elimination  of  cattle  affected  with  open  tuberculosis  a  marked  reduction  was 
obtained  in  tuberculosis  of  hogs,  and  that  this  measure  in  association  with  pasteuriza- 
tion of  the  skimmed  milk,  offers  a  certain  remedy  against  the  spread  of  tuberculosis  of 
hogs. 

The  same  opportunity  which  is  afforded  hogs  to  contract- 
tubercle  bacilli  from  the  feeding  of  skimmed  milk,  would  apply 
to  man.  The  relative  infrequency  of  the  infection  of  man  with 
the  bovine  type  of  tubercle  bacillus  is  not  the  result  of  a  milder 
virulence  of  the  bacilli  but  is  due  to  the  previous  boiling  of  the 
milk.  Convincing  observations  have  also  been  made  on  this  point. 

However  before  entering  into  a  discussion  of  these,  it  will  be 
advisable  to  illustrate  further  the  possibility  of  infection  for  man 
from  the  standpoint  of  the  port  of  entry,  and  also  show  the  relative 
condition  existing  between  the  necessary  infective  quantity  of 
bacteria  and  the  establishment  of  the  disease. 


Ingestion  Tuberculosis. 


The  development  of  the  affection  depends  on  the  most  varied 
conditions,  on  the  quantity  of  the  introduced  virus,  condition  of 
the  port  of  entry,  general  resistance,  etc. 

Frequency  of  Tuberculous  Infection  Through  the 
Alimentary  Tract. 

If  the  lesser  virulence  of  the  bovine  type  for  man,  as  compared 
to  the  human  type,  is  left  out  of  consideration,  which  fact  is  con- 
sidered satisfactorily  proven,  the  experiments  of  Ostermann, 
Schroeder  and  Cotton  show  what  great  quantities  of  infectious  ma- 
terial are  necessary  in  order  to  produce  tuberculosis  by  ingestion. 

Schroeder  and  Cotton  fed  milk  artificially  infected  with  tuber- 
cle bacilli,  and  proved  that  infected  milk  which  invariably  produced 
tuberculosis  when  inoculated  intraabdominally  in  5  c.  c.  doses, 
could  be  fed  for  30  days  without  causing  the  disease  in  the  ex- 
perimental animals. 

The  dilutions  were  prepared  (1)  by  adding  one  platinum  loopful  of  a  cloudy  sus- 
pension of  tubercle  bacilli  to  10  c.  c.  of  milk.  (2)  by  adding  one  loopful  of  the  orig- 
inal suspension  to  10  c.  c.  of  sterile  water,  and  of  this  dilution  one  loopful  was  placed 
into  10  c.  c.  of  milk,  (3)  by  adding  one  loopful  of  the  original  suspension  to  100  c.  c.  of 
sterile  water  and  of  this  dilution  one  loopful  was  placed  into  10  c.  e.  of  milk.  It  was 
not  possible  to  produce  ingestion  tuberculosis  with  either  the  second  or  third  dilution 
during  the  period  of  the  experiment,  although  the  dilutions  were  not  as  high  as  they 
occur  in  the  milk  of  tuberculous  animals  (with  the  exception  of  tuberculosis  of  the 
udder). 

Ostermann  by  comparing  the  average  number  of  tubercle 
bacilli  in  cow's  milk  with  the  minimal  dose  necessary  for  producing 
ingestion  tuberculosis  in  guinea  pigs,  rabbits  and  goats,  came  to 
the  conclusion  that  an  alimentary  infection  is  exceedingly  rare. 

Nevertheless  the  danger  of  an  alimentary  infection  with  bovine 
tubercle  bacilli,  even  in  high  dilutions  of  the  tuberculous  material 
in  market  milk,  cannot  be  disregarded. 

The  danger  of  infection  to  which  small  children  are  exposed 
from  the  ingestion  of  food  (without  attempting  to  distinguish  "bo- 
vine tuberculosis"  from  "human  tuberculosis")  is  best  illustrated 
by  the  clinical  cases  and  also  those  cases  of  intestinal  and  mesen- 
teric  tuberculosis  which  are  found  on  autopsy. 

Edens,  from  October  1,  1904,  to  September  30,  1905,  found 
12%,  and  from  this  time  until  September  30,  1906,  13.6%  of  the 
bodies  of  children  which  he  autopsied  at  the  ages  of  1  to  15  years, 
affected  with  primary  intestinal  tuberculosis  or  tuberculosis  of 
the  mesenteric  lymph  glands,  whereas  in  man  from  15  to  19  years 
of  age  only  3.8%  and  2.6%,  respectively  (all  autopsies),  showed 
the  disease. 

The  intestinal  tract  of  children  appears  therefore  to  be  a 
prominent  port  of  entry  for  the  tubercle  bacillus,  which  is  also 
proven  by  the  works  of  Orth,  Henke,  Chiechanowski,  Hamburger, 
Nebelthau,  Lubarsch,  Bruning,  Fibiger  and  Jensen,  Symes  and 
Fischer,  Price  and  Jones,  Kingsford,  Harbitz,  Ogyia,  Edens, 
Wagener  and  Heller,  who  demonstrated  primary  intestinal  tuber- 


JOS  Tuberculosis. 


culosis  in  varying  proportions,  up  to  47.6%  of  the  tuberculous 
children.  The  frequency,  however,  with  which  tubercle  bacilli 
actually  pass  through  the  intestinal  wall  without  producing  demon- 
strable changes  in  the  intestines  and  mesenteric  lymph  glands 
cannot  be  stated.  The  intestinal  tract  may  be  the  avenue  of 
infection  without  itself  or  its  regional  lymph  glands  becoming  in- 
fected. The  percentage  given  above  should  therefore  be  higher. 
The  works  of  McFadyean,  MacConkey,  Harbitz,  Weichselbaum, 
Bartel,  Rosenberger,  Rabinowitsch,  Ipsen  and  others  offer  proof 
for  this  contention,  as  they  mention  cases  in  which  apparently 
healthy  mesenteric  lymph  glands  contained  tubercle  bacilli  which 
although  appearing  to  be  in  a  latent  form  at  the  time  of  finding, 
produced  tuberculosis  when  inoculated  into  experimental  animals. 
It  appears  also  to  be  proven  experimentally  that  through  the 
feeding  of  tuberculous  material  tuberculosis  of  the  lungs  may 
develop  without  the  presence  of  intestinal  tuberculosis  or  tuber- 
culosis of  the  mesenteric  glands  (Bartel,  Bongert,  Kovacs  and 
others).  In  this  regard  the  question  may  be  raised  as  to  whether 
there  is  any  possibility  of  the  tubercle  bacilli  working  up  from 
the  intestines  into  the  esophagus,  and  into  the  buccal  cavity, 
from  which  inhalation  tuberculosis  could  result  (Uffenheimer, 
Dieterlen). 

This  objection  would  not  enter  into  consideration  for  the  pur- 
pose of  milk  control,  since  it  is  immaterial  for  the  hygienist  work- 
ing along  practical  lines,  whether  the  infectious  agent  causes  dis- 
ease in  the  body  by  way  of  the  circulation  or  through  inhalation. 
In  this  instance  it  is  only  necessary  to  keep  in  view  preventive 
measures,  which  should  completely  prevent  the  body  from  com- 
ing in  contact  with  producers  of  the  infection. 

Alimentary  Infection  of  Man  With  Bovine  Tuberculosis. 

After  the  supposed  cases  of  transmission  of  the  bovine  tuber- 
cle bacillus  cited  in  former  years  failed  to  withstand  critical 
observations,  Koch  at  the  International  Tuberculosis  Conference, 
held  in  Berlin,  in  1902,  urged  the  following  up  of  all  cases 
of  established  tuberculosis  of  the  udder,  the  determination  of  how 
long  the  disease  persisted,  who  consumed  the  milk  and  milk  pro- 
ducts from  these  cases,  whether  the  milk  had  been  boiled  and 
whether  the  respective  persons  became  affected  with  tuberculosis. 

This  request  was  fruitful  of  results,  and  in  1910  Weber  pub- 
lished the  results  of  his  compilation  investigations,  which  were 
carried  out  by  the  aid  of  official  statistics  from  Prussia,  Bavaria, 
Saxony,  Wurttemberg,  Baden  and  Hessen. 

The  investigations  extended  over  the  time  between  the  be- 
ginning of  1905  to  April,  1909;  the  investigation  of  some  of  the 
individual  cases  however  is  still  being  continued,  since  in  the 
chronic  courses  of  tuberculosis  it  must  be  considered  that  the 


Bovine   Tuberculosis  in   Man.  1Q9 

results  of  infection  with  bovine  tubercle  bacilli  may  under  certain 
conditions  only  manifest  themselves  after  years  have  elapsed. 

In  the  given  period  113  cases  were  reported,  of  which  68  were 
from  Prussia,  14  from  Bavaria,  6  from  Saxony,  6  from  Wurttem- 
berg,  10  from  Baden,  and  9  from  Hessen. 

At  least  628  persons  came  under  consideration  in  the  inges- 
tion  of  such  milk,  possibly  even  more,  since  at  times  only  the  term 
11  family"  is  designated,  and  the  milk  was  not  infrequently  deliv- 
ered to  dairies  with  a  large  patronage.  These  cases  were  not  in- 
cluded, although  every  person  is  exposed  to  an  infection  who  par- 
takes of  such  milk  and  dairy  products. 

In  the  case  of  9  persons  no  age  is  given;  284  were  children, 
and  385  adults. 

The  value  of  the  individual  cases  must  of  course  be  judged 
in  different  ways. 

In  44  cases  it  is  stated  that  the  milk  had  been  consumed  only 
as  an  addition  to  coffee,  or  mixed  with  milk  of  healthy  animals,  or 
the  data  were  otherwise  not  accurate. 

Of  especially  great  interest  are  those  cases  in  which  it  was 
emphasized  that  the  milk  was  consumed  in  a  raw  state,  unmixed, 
mixed  with  milk  of  only  a  few  cows,  or  in  which  such  milk  was 
used  in  the  preparation  of  butter,  buttermilk,  sour  milk,  or  had 
been  consumed  for  a  long  period.  In  such  cases  tremendous  num- 
bers of  tubercle  bacilli  must  have  been  taken  into  the  digestive 
tract.  According  to  Bang  and  Wall  the  milk  from  tuberculous 
udders  may  retain  a  normal  appearance  for  months,  being  used 
as  food  without  any  objection,  and  yet  such  milk  contains  millions 
of  tubercle  bacilli.  Bang  found  in  smear  preparations  of  such 
milk,  in  a  single  field  as  many  as  200  bacilli. 

In  all  69  cases  were  reported,  in  which  it  was  stated  with  cer- 
tainty that  raw  milk  of  animals  with  udder  tuberculosis,  or  pro- 
ducts prepared  from  such  milk,  were  consumed. 

The  milk  was  taken  for  a  longer  or  shorter  time,  in  large 
quantities,  by  151  children,  200  adults,  and  9  persons  whose  age 
was  not  mentioned. 

These  persons  are  divided  by  Weber  according  to  the  results 
of  the  investigations,  into  four  groups,  namely: 

1.  Cases,  in  which  an  infection  occurred  of  a  bovine  type. 

2.  Those  in  which  a  suspicion  of  an  infection  exists,  but 
on   account  of  insufficient  bacteriological  examinations   has   not 
yet  been  determined. 

3.  In   affections   in   which  the   bacteriological   examination 
relative  to  the  suspicion  of  tuberculosis  was  negative,  or  in  which 
the  human  type  was  found  exclusively,  and 

4.  Cases  in  which  no  affections  whatsoever  have  been  dem- 
onstrated up  to  the  present  time. 

In  Group  1  an  infection  with  the  bovine  type  was  demonstrated 
in  two  families,  affecting  one  child  in  each. 


110  Tuberculosis. 


In  both  cases  it  was  possible  to  trace  the  consumption  of  mill 
containing  the  bacilli  up  to  the  nursing  age.  In  one  case  it  laste( 
for  one  and  a  half  years,  in  the  second  case  one  year,  and  in  th< 
latter  case  the  udder  affection  had  been  recognized  for  thre< 
months  during  the  period  that  the  child  had  been  using  the  milk 

In  both  cases  the  respective  cow  was  affected  with  a  sever* 
tuberculosis  of  the  udder  in  all  four  quarters ;  the  milk  had  beei 
consumed  at  all  times  mixed  with  the  milk  of  a  second  cow,  in  th< 
first  case  boiled  or  raw  but  in  the  second  case  only  raw. 

The  other  members  of  the  family  remained  well  in  spite  o: 
the  consumption  of  this  milk ;  in  both  instances  only  the  younges 
child  became  affected  with  tuberculosis  of  the  cervical  glands. 

In  the  first  case  another  child  of  four,  and  one  of  five  years 
was  included  in  the  family ;  in  the  second  case  children  of  the  ag< 
of  3,  4,  7,  8,  9  and  12  participated  in  the  consumption  of  the  milk 
all  remaining  normal. 

The  tuberculosis  of  the  cervical  glands  healed  in  the  tw( 
youngest  after  abscess  formations,  leaving  several  slightly  en 
larged  small  glands  in  the  surrounding  parts.  One  of  the  boys 
appears  to  be  in  the  best  of  health,  the  other  is  somewhat  behind  ii 
his  development  (at  the  age  of  2  %  years  he  weighs  25fbs.) ;  in  tin 
last  six  weeks  however  his  weight  increased  slightly  more  thai 
1  lb. 

In  the  cases  of  the  second  group  there  exists  suspicion  of  { 
bovine  type  of  infection. 

In  six  children  and  one  adult  there  are  swellings  of  the  cervi 
cal  lymph  glands  and  in  four  children  and  one  adult  a  suspicioi 
of  abdominal  tuberculosis  is  given.  One  child  is  affected  witl 
scrofula.  In  the  four  children  the  manifestations  of  disease  re 
trogressed,  while  in  the  adult  it  appears  doubtful,  according  t( 
Weber,  whether  the  affection  is  of  a  tuberculous  nature. 

Forty-one  persons  are  included  in  Group  3,  who  consumec 
milk  in  a  raw  state  from  cows  affected  with  tuberculosis  of  th< 
udder.  This  was  at  times  mixed  with  milk  of  other  cows.  A  girl  o: 
16  years  of  age  and  a  boy  four  years  old,  who  died  of  tuberculosis 
were  included  in  this  group.  The  producers  of  their  infections 
were  bacilli  of  the  human  type.  A  man  and  a  woman  who  wer( 
affected  with  pulmonary  tuberculosis  (human  type),  a  boy  witl 
suppuration  of  the  middle  ear  and  cervical  lymph  glands  (no' 
tubercular) ;  an  18-year  old  boy  with  rheumatism  of  the  joints 
and  valvular  heart  trouble,  chronic  diarrhea  and  pulmonary  symp 
toms  (not  tubercular) ;  a  woman  with  catarrh  of  the  apex  of  th( 
lungs  (not  tubercular) ;  a  woman  with  swelling  of  the  glands 
diarrhea,  cough,  night  sweats  and  emaciation  (inoculation  o1 
sputum  without  results),  and  a  woman  and  a  man  with  pulmonary 
symptoms  (not  tubercular)*  were  also  in  the  total  of  forty-one. 

The  cases  in  which  a  boy  and  a  girl  died  from  tuberculosis 
are  of  especial  importance.  In  spite  of  the  prolonged  consump 


Table  III. 


Milk  from  a  tuberculous  udder.      1  X  1200. 


Ernst,  Milk  Hygiene. 


Danger  from  Bovine  Tuberculosis. 


tion  of  raw  milk  from  a  tuberculous  udder  by  the  children  who 
were  already  infected  with  the  human  type  of  the  disease,  it  was 
impossible  to  isolate  from  the  tuberculous  glands  of  the  neck  and 
mesentery  any  bacilli  of  the  bovine  type.  Weber  concludes  from 
this  that  a  body  already  infected  with  the  human  type  of  the  dis- 
ease is  resistant  rather  than  susceptible  towards  an  infection  with 
the  bovine  type. 

The  fourth  group  contains  by  far  the  greatest  number  of 
cases  in  which  children  and  adults  consumed  raw  milk  from  cows 
affected  with  tuberculosis  of  the  udder,  or  milk  products  prepared 
from  the  same,  and  includes  those  cases  in  which  no  disturbances 
of  the  health  resulted  from  such  consumption.  It  was  especially 
stated  relative  to  the  children  that  they  all  appeared  thriving  and 
healthy.  Among  these  persons  are  included  those  who  for  a  long 
period  ingested  especially  great  quantities  of  bovine  tubercle  ba- 
cilli ;  thus  a  13-month  old  child  has  been  brought  up  exclusively  on 
raw  and  boiled  milk  from  a  cow  affected  with  udder  tuberculosis, 
and  up  to  the  present  remains  healthy. 

Other  cases  may  be  considered  as  presenting  complete  ex- 
periments with  the  necessary  controls,  since  the  persons  who 
drank  the  milk  remained  healthy,  whereas  calves  and  hogs  fed  with 
the  same  milk  developed  severe  ingestion  tuberculosis.  The  ob- 
servations of  such  cases  may  be  traced  back  incompletely  for 
3  or  4  years. 

A  25-year  old  waitress,  and  a  28-year  old  dairy  hand  drank  mugfuls  of  freshly 
drawn  tuberculous  milk,  frequently  without  any  other  milk  being  added  without  be- 
coming affected;  the  calf  of  the  cow  which  produced  the  milk  had  to  be  slaughtered 
after  four  weeks,  and  showed  tuberculosis  of  the  mesenteric  lymph  glands,  liver,  lungs 
and  kidneys,  a  severe  ingestion  tuberculosis. 

The  milk  of  another  highly  affected  tuberculous  cow  also  suffering  from  udder 
tuberculosis,  was  mixed  with  the  milk  of  two  other  cows,  and  was  consumed  frequently 
in  a  raw  condition,  by  two  adults  and  a  13-year  child;  a  child  1%  years  of  age  was 
given  the  milk  only  in  a  boiled  condition.  The  adults  remained  healthy;  the  calf  from 
this  cow  had  to  be  slaughtered  after  five  weeks,  and  showed  generalized  tuberculosis. 

From  the  stable  of  a  herdsman  the  milk  of  a  cow  affected  with  udder  tuberculosis 
was  mixed  with  the  milk  of  three  other  cows,  and  the  cream  and  butter  prepared  from 
this  was  consumed  by  four  persons,  aged  31  to  59  years,  without  producing  any  ill 
effects.  The  five  hogs  of  the  herdsman  were  found  on  postmortem  to  be  tuberculous. 

Similar  results  were  reported  from  the  ingestion  of  milk  from  a  tuberculous  udder 
of  a  goat,  which  was  consumed  as  raw  and  boiled  milk  by  three  adults  and  four  chil- 
dren of  ages  from  5  to  16  years.  The  persons  remained  well  while  a  hog  became  af- 
fected with  ingestion  tuberculosis. 

In  two  other  cases  the  milk  was  consumed  in  a  raw  or  unmixed  state,  as  milk, 
buttermilk  and  butter.  It  was  consumed  by  seven  adults,  in  one  case  for  a  period  of 
four  months,  in  another  case  even  longer.  In  spite  of  the  fact  that  the  family  has  been 
kept  under  observation  for  four  years  no  disturbance  in  health  can  be  detected. 

It  is  proven  by  the  collected  material  of  Weber  that  even 
though  tremendous  quantities  of  tuberculous  material  are  con- 
sumed, still  more  favoring  accessory  conditions  are  necessary  in 
order  to  produce  an  infection  with  the  bovine  type  of  tubercle 
bacilli.  Of  course  it  is  not  yet  known,  as  indicated  by  Weber,  how 
many  of  the  children  which  show  swelling  of  the  cervical  lymph 
glands  and  symptoms  of  suspected  abdominal  tuberculosis,  are 


112  Tuberculosis. 


affected  with  the  bovine  type  of  tuberculosis,  or  how  many  of  the 
persons  who  fail  to  show  any  disturbance  of  health  may  harbor 
one  or  more  infected  mesenteric  glands ;  likewise  it  is  not  known 
how  many  children  with  a  latent  form  of  the  disease  may  through 
a  special  weakening,  or  under  the  influence  of  other  infections, 
break  down  later  with  tuberculosis,  possibly  even  with  a  fatal 
termination. 

Through  the  compilation  investigations  we  know  only  of  the 
time  (which  extends  over  a  period  of  1-3-4  years  in  the  individual 
cases),  the  opportunity  and  the  immediate  results  of  the  infection, 
and  not  the  further  development  of  the  same,  but  we  do  know  that 
in  two  children  a  true  bovine  type  of  tuberculosis  existed. 

Therefore,  although  a  possibility  of  infection  was  present  in 
a  great  number  of  persons,  the  infection  has  positively  occurred 
up  to  the  present  only  in  two  children  in  infancy.  This  constitutes 
proof  that  "the  danger  which  threatens  man  from  the  consumption 
of  milk  and  milk  products  from  cows  affected  with  udder  tubercu- 
losis is  very  slight  when  compared  with  the  danger  of  man  affected 
with  open  pulmonary  tuberculosis  to  his  fellow  men." 

This  conclusion  of  Weber  may  be  supported  without  further 
consideration.  Nevertheless  the  danger  still  prevails,  and  al- 
though it  is  slight  in  comparison  with  the  danger  through  infec- 
tion with  the  human  type,  it  should  be  by  no  means  under-esti- 
mated; it  should  be  considered  that  the  danger  of  infection  with 
human  tuberculosis  is  amazingly  great,  and  the  opportunity  of 
ingesting  the  bovine  type  of  tubercle  bacillus  with  milk  is  similarly 
great. 

Bovine  Tuberculosis  in  Man  in  General. 

Although  the  attention  of  pathologists  of  all  countries  has 
been  directed  for  the  last  ten  years  to  infections  of  man  with  bovine 
tuberculosis,  up  to  the  present  time  there  are  collected  only  117  cer- 
tain cases  of  bovine  tuberculosis  in  children  and  21  cases  in  adults 
(over  16  years  of  age). 

Of  the  117  cases  in  grown  children  105  are  accurately  de- 
scribed, and  invojve  the  following  organs : 
60  cases  of  abdominal  tuberculosis 
25  cases  of  tuberculosis  of  the  cervical  glands 
4  cases  of  tuberculosis  of  the  tonsils 
7  cases  were  generalized 

3  cases  were  localized  in  the  bones  and  joints 
6  cases  represented  lupus 

Two  cases  should  also  be  included  in  which  bovine  bacilli  were 
found  in  unchanged  lymph  glands. 

The  60  cases  of  abdominal  tuberculosis  are  again  divided  into 
34  severe  cases  in  which  the  mesenteric  lymph  glands,  the  intes- 
tines and  the  peritoneum  showed  changes.  Thirty  of  these  after 
generalization  of  the  affection,  terminated  in  death. 


Bovine   Tuberculosis  in   Man. 


Twelve  of  the  60  patients  had  tuberculosis  of  the  mesenteric 
glands,  slight  intestinal  tuberculosis,  and  tuberculous  meningitis. 
The  12  cases  were  severe  fatal  affections. 

In  14  cases  the  autopsy  revealed  tuberculosis  of  the  mesen- 
teric lymph  glands  with  the  bovine  type  of  bacilli,  but  this  was 
found  accidentally  following  other  causes  of  death,  as  diphtheria, 
scarlet  fever,  measles,  and  pneumonia. 

In  the  21  adults  the  bovine  type  of  the  disease  was  established 
three  times  in  pulmonary  tuberculosis  with  expectorations,  once 
in  a  primary  abdominal  tuberculosis  and  pulmonary  tuberculosis, 
once  in  an  infection  of  the  buccal  mucous  membrane  and  cervical 
lymph  glands,  once  each  in  tuberculosis  of  the  knee  joints,  the  kid- 
neys and  the  peritoneum,  and  finally  the  bacillus  of  bovine  type 
was  isolated  from  three  cases  of  lupus,  two  cases  of  skin  tuber- 
culosis, and  five  cases  of  tuberculosis  verrucosa  cutis  in  butchers. 
Besides  these  instances  the  bovine  type  of  tubercle  bacillus  was 
isolated  three  times  from  the  mesenteric  glands  of  adults. 

In  two  cases  of  phthisis  the  bovine  tubercle  bacillus  was  found 
in  association  with  the  human  type. 

Of  the  total  of  138  cases,  56  were  fatal,  and  89  could  be  ex- 
plained with  certainty  or  with  the  greatest  probability  as  inges- 
tion  tuberculosis.  The  other  forms  of  tuberculosis,  with  the  ex- 
ception of  the  skin  tuberculosis  of  the  butchers  and  of  one  milker, 
may  also  probably  be  traced  to  the  same  mode  of  infection. 

Weber  deduces  from  his  findings  that  the  danger  of  becoming 
infected  with  tubercle  bacilli  of  cattle  is  great  for  the  individual, 
but  is  only  slight  for  the  human  race  as  a  whole. 

Kossel  reports  in  the  German  Medical  Weekly  relative  to  the 
number  of  cases  of  animal  tuberculosis  in  man  as  compared  with 
the  human  type  of  tuberculosis,  and  observed  that  in  1602  cases 
of  human  tuberculosis  the  bovine  type  appeared  as  the  infective 
agent  in  126  cases,  the  human  type  alone  in  1464  cases,  the  human 
and  bovine  type  in  association  nine  times,  and  the  avian  type  of 
tubercle  bacillus  three  times.  Therefore  in  about  8.6%  of  human 
tuberculosis,  bacilli  of  animal  origin  were  found,  and  in  about  8% 
of  these  they  were  of  the  bovine  character.  If  however  the  most 
frequent  form  of  tuberculosis  of  man  is  considered,  namely  pul- 
monary tuberculosis,  then  the  bovine  type  can  be  demonstrated 
only  in  about  .6%  of  the  cases,  whereas  in  the  other  forms  of 
tuberculosis  it  may  be  found  in  16%  of  the  cases. 

Tuberculosis  of  bovine  origin  occurs  most  frequently  in  chil- 
dren in  which  tuberculosis  of  the  cervical  glands  is  caused  in  about 
40%  of  the  cases  from  infections  with  the  bovine  type,  and  tuber- 
culosis of  the  mensenteric  glands  may  be  traced  to  the  same  type  in 
40  to  50%  of  the  cases.  A  portion  of  these  affections,  as  has  al- 
ready been  mentioned,  may  terminate  fatally.  Among  the  fatal 
forms  of  tuberculosis  in  children  76%  are  caused  by  the  human 
type  and  24%  by  the  bovine  form.  The  meningitis  type  of  the 


Tuberculosis. 


disease  is  brought  on  in  only  about  11%  of  the  cases  by  the  bacil- 
lus of  animal  origin  and  in  89%  by  the  human  type  of  the  organism. 

In  tuberculosis  of  the  bones  and  joints  the  figures  are  5% 
and  95%  respectively. 

Gaffky,  Kothe  and  Ungermann  found  in  400  bodies  of  children, 
76  infections  with  tuberculosis,  in  which  they  succeeded  in  estab- 
lishing the  variety  of  the  bacillus.  In  one  case  they  found  the 
bovine  type  (1.32%),  and  among  171  other  autopsies  on  children, 
of  which  39  were  tuberculous,  two  (5.1%)  cases  of  bovine  infection 
were  observed. 

The  results  of  tuberculous  infections  among  children  of  the 
population  of  Berlin  were  therefore  95  to  96%  of  human  origin, 
while  only  4  to  5  %  were  of  bovine  origin,  iii  spite  of  the  fact 
that  during  infancy  the  danger  of  bovine  infection  is  the  greatest 
(Kossel). 

[According  to  figures  compiled  by  Park  of  the  New  York 
City  Board  of  Health,  the  frequency  of  bovine  tuberculosis  in  man 
as  collected  by  various  investigators  is  as  follows : 

In  adults,  955  cases  have  been  examined  of  which  940  showed 
human  infection  and  15  bovine  infection.  In  children  from  five 
to  sixteen  years  of  age,  out  of  177  cases  investigated,  131  were 
human  infections  and  46  bovine  infections.  Among  children  under 
five  years  old  there  were  368  cases  of  which  292  were  found  in- 
fected with  the  human  type  and  76  with  the  bovine  type  of  tuber- 
culosis. Furthermore  Park  mentions  the  very  suggestive  results 
obtained  from  nine  children  under  6  years  of  age  who  were  fed 
exclusively  on  cow's  milk  at  the  Foundlings'  Hospital.  Five  of 
these  children  died  of  bovine  infection  and  four  of  human  infec- 
tion. On  the  other  hand  in  the  Babies'  Hospital  where  the  infants 
are  nursed  or  fed  on  prescription  milk,  out  of  63  children  dying 
of  tuberculosis,  59  proved  to  be  human  infection  and  4  bovine 
infection. 

The  figures  taken  from  clinical  work  in  England  indicate  that 
from  23  to  25%  of  the  fatal  cases  of  tuberculosis  in  children  are 
due  to  bovine  infections.  Stiles  of  Edinburgh  has  presented  in- 
teresting statistics  to  illustrate  how  bovine  tuberculosis  particular- 
ly affects  young  children.  Of  67  consecutive  tuberculous  bone  and 
joint  cases,  the  bovine  bacillus  was  present  in  41,  the  human  bacil- 
lus in  23,  while  in  3  cases  both  types  were  present.  In  those  af- 
fected children  under  12  months  old,  only  the  bovine  bacillus  was 
found.  Of  the  12  children  between  1  and  2  years  of  age,  8  owed 
their  disease  to  bovine  infection,  2  to  human  infection  and  2  to 
both  bovine  and  human  infection.  There  were  15  cases  in  2  to  3 
year  old  children,  11  of  which  were  bovine,  3  human  and  1  both 
infections.  The  10  cases  from  the  3  to  4  year  period  were  6  bovine 
and  4  human  infections,  while  the  4  to  5  year  period  included  3 
cases  of  each  type  of  infection.  Stiles  further  reports  on  72  cases 
of  tuberculous  cervical  glands  operated  on  at  the  Children's  Hospi- 


Control  of  Bovine  Tuberculosis. 


tal  in  Edinburgh,  in  which  the  disease  was  due  to  the  bovine  bacil- 
lus in  65  cases,  while  in  only  7  patients  was  the  disease  caused  by 
the  human  bacillus.  —  Trans.] 

Conclusions. 

If  we  compile  the  results  of  this  chapter  the  following  conclu- 
sions may  be  established: 

Although  tuberculosis  of  cattle  is  less  dangerous  for  man  than 
tuberculosis  of  man,  the  danger  from  the  enormous  spread  of  the 
disease  in  our  herds,  and  especially  among  the  dairy  cows,  should 
in  no  way  be  under-estimated.  Theoretically  the  possibility  of 
infection  is  afforded  in  all  cases  in  which  the  ingestion  of  living 
tubercle  bacilli  with  the  milk  takes  place  ;  from  a  practical  stand- 
point however  this  possibility  of  infection  comes  into  consideration 
only  when  the  bacilli  enter  the  individual  in  great  quantities,  and 
the  resistance  (of  a  local  or  general  nature)  of  the  body  is  not 
equal  to  this  quantitative  attack.  This  disposition,  or  these  rela- 
tive conditions  between  the  injurious  agents  and  resistance,  appear 
to  be  especially  unfavorable  in  children  ;  therefore  the  requirement 
of  the  elimination  from  dairy  herds  of  all  tuberculous  animals 
which  pass  tubercle  bacilli  writh  their  milk,  appears  to  follow  as  a 
matter  of  course.  According  to  the  experience  at  the  tuberculosis 
eradication  stations  only  those  animals  must  be  considered  as 
eliminators  of  tubercle  bacilli  wrhich  are  affected  with  open  tuber- 
culosis, and  expel  the  tubercle  bacilli  with  their  secretions  and 
excretions,  especially  animals  affected  with  tuberculosis  of  the 
udder,  open  pulmonary  tuberculosis,  tuberculosis  of  the  uterus, 
intestinal  tuberculosis,  and  furthermore  animals  with  tuberculosis 
of  the  liver,  kidneys,  skin,  eyes,  and  larynx. 

Measures  Against  the  Danger. 

The  elimination  of  animals  passing  tubercle  bacilli  should 
also  be  energetically  encouraged  on  general  economic  grounds. 
For  this  work  three  methods  may  be  followed  : 

1.  Treatment  of  the  disease  and  curative  attempts. 

2.  The  immunization  of  healthy  herds. 

3.  Energetic  sanitary  police  eradication  measures,  reduction 
of  the  possibilities  of  infection,  and  protection  of  young  animals 
from  infection,  together  with  favorable  conditions  for  bringing 
up  young  stock  as  a  preventive  measure  against  their  accidental 
infection,  toward  which  we  are  powerless. 

The  curative  measures  in  affected  animals  may  be  left  out  of 
consideration  as  measures  of  control,  since  —  excepting  the  uni- 
formly bad  or  only  slightly  favorable  results  —  the  methods  of 
treatment  for  veterinary  practice  are  too  complicated,  and  are 
not  practicable  in  consideration  of  the  value  of  the  animal.  For 
the  sake  of  completeness  the  experiments  with  iodipin  should  be 
mentioned  here  (Hauptmann).  Creosote  has  also  been  employed. 


Tuberculosis. 


Of  the  specific  remedies,  tuberculin,  tulase,  tulase-lactin, 
tulon  and  tuberculase  could  be  considered  in  the  treatment  of 
affected  animals.  These  bacterial  preparations,  however,  accord- 
ing to  Romer  and  Arloing,  are  ineffective,  since  the  results  were 
negative. 

Better  results  were  promised  at  the  onset,  from  the  specific 
immunization  methods,  which  aimed  at  a  systematic  preliminary 
treatment  with  slightly  virulent  strains,  or  with  attenuated  bovine 
tubercle  bacilli,  to  increase  artificially  the  resistance  of  the  im- 
munized animals,  that  is,  to  protect  them  against  a  later  accidental 
natural  infection.  As  a  matter  of  fact  cattle  immunized  with 
tubercle  bacilli  prove  for  a  time  to  be  immune,  or  at  least  manifest 
a  considerable  resistance  against  a  subsequent  artificial  infection 
with  bovine  tubercle  bacilli,  when  compared  with  non-immunized 
control  animals.  For  immunization  purposes  there  have  been 
used: 

1.  Dry  tubercle  bacilli  of  the  human  type  (bovo-vaccine,  Von 
Behring's  method).  The  injection  is  made  into  the  blood  circula- 
tion and  is  repeated.  Animals  treated  in  this  way  after  3  to  4 
months,  resist  an  intravenous  injection  of  bovine  tubercle  bacilli, 
to  which  untreated  animals  invariably  succumb.  This  increased 
resistance  however  lasts  only  a  short  time.  According  to  the  in- 
vestigations of  Rossignol  and  Vallee  and  Hutyra  it  diminishes  to- 
wards the  end  of  a  year,  and  after  another  six  months  it  practically 
disappears.  Against  the  slight  practical  success  of  this  method 
the  disagreeable  fact  should  be  considered  that  the  injected  tubercle 
bacilli  of  man  are  retained  alive  in  the  body  of  the  cattle  for  years, 
and  may  even  produce  in  the  udder  local  tuberculous  processes, 
from  which  the  bacteria  of  human  tuberculosis  may  enter  into  the 
milk  (Lignieres,  Weber  and  Titze). 

Titze  found  that  following  an  intravenous  injection  of  human  tubercle  bacilli, 
they  were  eliminated  from  the  udder  even  16  months  after  the  injection.  In  this  regard 
the  various  individuals  manifest  an  entirely  different  behavior.  In  three  other  cases 
bacteria  were  eliminated  after  a  single  injection,  from  the  fourth  week  up  to  the  144th 
day.  In  a  second  cow  which  received  an  injection  of  tubercle  bacilli  of  human  and 
bovine  type  the  elimination  commenced  after  the  third  injection,  and  in  a  third  cow  as 
early  as  24  hours  after  the  injection.  All  three  animals  eliminated  the  bacilli  from  only  one 
quarter,  without  this  showing  tuberculous  changes. 

Bongert  found  in  186  bovo-vaccinated  cattle,  36  which  passed  tubercle  bacilli 
with  their  milk. 

The  protective  vaccination  of  Von  Bearing  therefore  is  not 
only  of  little  practical  value,  but  grave  dangers  must  be  considered 
in  connection  with  it,  since  the  vaccinated  animal  may  eliminate 
tubercle  bacilli  with  the  milk  for  2y2  years  and  longer. 

Koch  and  Schiitz,  Neufeld  and  Miessner  recommended  for  the 
immunization  of  cattle  a  single  injection  of  0.01  gm.  tubercle 
bacilli  in  suspension,  which  vaccine  they  termed  ' '  tauruman. ' '  The 
above  statement  applies  equally  for  tauruman  as  it  does  for 
bovo-vaccine.  Similar  results  to  the  immunizing  value  of  the  in- 
travenous injections,  according  to  Baumgarten,  Lignieres  and 


Tuberculosis    Vaccination. 


Klimmer  may  be  derived  from  the  single  subcutaneous  admin- 
istration of  human  tubercle  bacilli.  According  to  Lignieres  even 
in  such  cases  the  bacteria  may  remain  alive  for  as  long  as  two 
years. 

According  to  Von  Behring,  Calmette  and  Guerin,  Roux  and  Vallee,  cattle  may 
become  immunized  by  feeding  with  slight  quantities  of  bacilli  from  tuberculosis  of 
the  horse  (or  bovine  tuberculosis). 

Arloing  attempted  to  immunize  with  homogenized  cultures  of  strains  which  had 
been  cultivated  in  6%  glycerine  bouillon  (human  type  and  bovine  type).  Better  results 
were  obtained  from  the  intravenous  than  from  the  subcutaneous  applications  and  this 
again  proved  superior  to  administration  per  os. 

Klimmer  eliminated  the  danger  of  the  vaccination  for  man  by 
heating  the  human  tubercle  bacilli  to  52-53  deg.  C.,  or  by  rendering 
them  avirulent  by  continuous  passages  through  the  crested  newt. 
Both  these  vaccines  are  no  longer  pathogenic  for  guinea  pigs,  and 
they  cannot  regain  their  virulence  by  means  of  passages  through 
animals.  The  results  of  immunizations  are  supposed  to  be  favora- 
ble (Klimmer  on  10,000  cattle),  especially  if  the  vaccination  is 
carried  out  together  with  general  protective  measures,  such  as 
raising  calves  on  milk  free  of  tuberculosis,  and  the  elimination  of 
animals  with  open  tuberculosis.  Glockner  even  believes  that  vac- 
cination has  a  favorable  action  on  the  curing  of  animals  which  were 
already  affected  with  bovine  tuberculosis  prior  to  the  vaccination, 
whereas  Eber  attributes  the  improvement  of  the  vaccinated  herds 
to  the  simultaneously  executed  prophylactic  and  hygienic  meas- 
ures. Friedmann  aimed  to  produce  immunization  with  his  tuber- 
cle bacillus  from  cold  blooded  animals  (turtle).  Other  authors 
however  failed  in  producing  an  effective  immunization  with  such 
strains  (Libbertz  and  Euppel,  Weber  and  Titze,  Orth). 

Heymanns  attempted  to  immunize  cattle  by  the  introduction 
under  the  skin  of  cattle  of  a  closed  sack  of  vegetable  fiber,  contain- 
ing living  tubercle  bacilli  (human  or  bovine  in  origin).  The  sup- 
position is  that  these  vegetable  sacks  will  confine  the  bacilli  at  the 
seat  of  inoculation,  and  that  the  treated  animal  will  be  immunized 
by  protective  metabolic  products,  that  continuously  form  in  small 
quantities  within  the  sack  and  pass  outward  from  it  into  the 
animal's  system  generally,  by  an  osmotic  process. 

The  vaccination,  which  is  carried  out  with  the  aid  of  a  tro- 
car to  insert  the  capsule  under  the  skin  of  the  back,  must  be  re- 
peated annually,  since  the  bacilli  may  die. 

Heymann's  method  has  been  successfully  used  by  its  discov- 
erer on  more  than  20,000  cattle,  and  the  percentage  of  reactors 
to  the  tuberculin  test  diminished  from  45  to  21  (18  herds  with  188 
animals).  Animals  which  have  formerly  reacted  may  appear  free 
at  the  subsequent  test. 

.  Good  results  were  obtained  by  Vallee  from  passive  immuniza- 
tion. He  inoculated  young  cattle  with  100  to  200  c.  c.  of  a  protec- 
tive serum,  which  he  obtained  from  a  horse  treated  with  slightly 
virulent  strains  from  horses,  and  then  with  strains  from  men. 


118  Tuberculosis. 


With  this  method  he  succeeded  in  rendering  the  animals  resistant 
to  artificial  infection  with  bovine  tubercle  bacilli. 

Since  immunization  methods  have  not  offered  uniformly 
satisfactory  results,  and  since  they  must  be  prohibited  on  the 
ground  of  milk  hygiene,  therefore  results  may  be  expected  only 
from  proved  sanitary  police  measures. 

The  methods  which  must  be  followed  in  the  eradication  of 
bovine  tuberculosis  are: 

1.  Diminution  or  elimination  of  the  sources  of  infection, 

(a)  By  removal  of  the  animals  passing  bacilli, 

(b)  By  separation  of  healthy  and  suspected  or  diseased 

animals, 

(c)  By  bringing  up  tuberculosis-free  young  animals. 

2.  Improvement  of  the  general  methods  in  the  care  of  young 
stock,  by  introducing  conditions  which  approach  the  natural  mode 
of  living: 

(a)  Proper  care  and  feeding  in  well  ventilated  and  lighted 

stables, 

(b)  Dividing  the  pastures  so  that  the  animals  may  be  sepa- 
rated (according  to  whether  they  are  suspected  or  healthy)  and 
kept  in  accordance  with  their  age  and  with  the  use  for  which  they 
are  later  intended. 

Measures  for  eradication  must  be  applied  in  accordance  with 
the  rules  here  outlined. 

The  most  effective  method  of  eradication  was  worked  out  by 
Bang,  and  consists  in  the  elimination  of  clinically  recognizable  dis- 
eased animals,  the  separation  of  reacting  animals,  and  the  bringing 
up  of  calves  on  milk  free  of  tubercle  bacilli. 

The  remarkable  value  of  Bang's  methods  has  been  proven  fully 
in  practice  by  the  results  obtained  since  1892. 

It  is  important  for  the  results  to  separate  completely  the 
animals  which  fail  to  react  to  tuberculin,  that  is  the  healthy  cattle, 
from  those  which  harbor  the  disease  and  which  react  to  the  tuber- 
culin test.  This  should  be  done  in  such  a  way  that  the  healthy 
animals  are  placed  in  a  freshly  disinfected  stable  or  in  a  portion 
of  a  stable  provided  with  a  separate  entrance,  and  separated  with 
a  board  wall,  from  that  part  in  which  the  reacting  cattle  are  housed. 
The  attendants  of  the  healthy  herd  should  not  come  in  contact  with 
those  of  the  diseased  herd.  Animals  of  the  reacting  group  which 
after  a  time  become  affected  so  that  they  may  be  clinically  recog- 
nized, should  be  slaughtered  as  soon  as  possible. 

Young  stock  which  react  should  not  be  permitted  to  breed,  or 
at  least  should  be  immediately  placed  with  the  reacting  group, 
providing  their  breeding  value  is  such  that  this  procedure  is 
deemed  advisable.  All  reacting  animals  under  six  months  of  age 
should  be  slaughtered,  that  is  they  should  be  utilized  for  meat. 

Young  stock  and  work  oxen  should  also  be  included  in  the 


Methods  of  Eradication. 


segregation,  and  the  healthy  ones  must  be  kept  from  contact  with 
reacting  animals. 

Of  the  calves  which  are  born  after  the  separation,  those  from 
non-reacting  cows  remain  with  their  mothers;  the  calves  from 
reacting  cows,  after  receiving  the  colostrum  from  their  mother  on 
the  first  day  after  birth,  should  be  placed  in  the  stable  of  healthy 
animals,  and  should  be  fed  with  the  milk  of  healthy  cows  or  should 
be  brought  up  on  sterilized  milk,  or  they  may  be  allowed  to  suck 
from  healthy  nurse  cows.  As  soon  as  possible  after  weaning  the 
calves  should  also  be  subjected  to  the  tuberculin  test,  and  those  giv- 
ing a  reaction  should  be  immediately  removed.  From  1  to  "2% 
of  these  calves  react. 

It  is  proper  to  place  the  healthy  calves  in  a  stable  of  healthy 
young  stock,  and  they  may  pasture  with  them,  or  if  this  is  not  pos- 
sible they  should  be  placed  with  the  older  non-reacting  group  of 
animals.  Before  the  first  breeding  the  heifers  again  should  be 
subjected  to  the  tuberculin  test,  in  order  to  place  them  in  the  prop- 
er group  of  cows. 

The  tuberculin  test  is  annually  repeated  in  the  healthy  herd, 
in  order  to  eliminate  the  animals  which  in  the  course  of  the  year 
have  had  a  possible  opportunity  of  becoming  affected  with 
tuberculosis. 

Newly  purchased  animals  are  clinically  examined  and  tested 
with  tuberculin,  and  are  added  to  the  healthy  herd  only  when  the 
results  are  entirely  satisfactory. 

The  male  animals  which  are  to  be  used  for  breeding  purposes 
should  not  react  to  the  tuberculin  test.  Under  unavoidable  cir- 
cumstances, a  reacting  bull  may  be  reserved  for  breeding  pur- 
poses but  only  under  special  precautionary  measures. 

The  results  of  Bang's  eradication  method,  if  carefully  carried 
out,  are  remarkably  satisfactory. 

It  has  been  adopted  to  the  greatest  extent  in  Denmark,  Sweden 
and  Norway,  and  it  has  also  been  successfully  carried  out  in  Hun- 
gary and  Finland. 

The  report  of  Regner,  in  1911,  affords  a  good  review  of  the 
results  of  Bang's  method,  and  in  it  are  described  the  results  of  the 
governmental  eradication  of  tuberculosis  in  Sweden.  Regner  di- 
vides the  eradication  work  into  an  offensive  one  in  herds  in  which 
the  disease  prevails,  and  into  a  defensive  procedure  whose  purpose 
is  the  prevention  of  the  introduction  of  diseased  animals  into  herds 
free  of  tuberculosis. 

Of  the  groups  into  which  Regner  separates  the  herds  and  the 
animals,  the  first  group  includes  those  which  originally  (on  the 
first  tuberculin  test  which  in  some  instances  was  applied  years 
previously)  were  found  tuberculous.  At  that  time  16,852  animals 
had  been  tested  with  a  percentage  of  30 . 2  reactors.  In  1908,  18,719 
animals  in  457  herds  proved  to  be  entirely  free  from  tuberculosis. 
%  The  herds  of  the  second  group,  which  proved  to  be  tuberculous 


120  Tuberculosis. 


at  the  time  of  the  inauguration  of  the  method  and  which  continued 
to  contain  reacting  animals,  included  375  herds  of  21,899  animals, 
with  41.5%  of  reactors.  At  the  end  of  1908  the  number  of  cattle 
had  increased  to  26,181,  of  which  only  1,496,  or  5.7%  reacted. 

The  results  were  not  so  pronounced  when  the  reacting  animals 
were  retained  with  the  healthy  animals,  when  cattle  without  the 
necessary  precautionary  measures  were  placed  in  herds  free  of 
tuberculosis,  when  animals  which  had  not  reacted  in  the  old  herd 
were  removed  into  the  free  herd  without  being  previously  tested, 
or  when  an  opportunity  was  given  for  the  transmission  of  the  in- 
fection by  a  reacting  bull  causing  the  infection  in  the  herd  to  ap- 
pear to  be  renewed.  Also  in  cases  when  the  milk  used  for  the  feed- 
ing of  calves  was  not  free  from  tubercle  bacilli,  the  results  were 
unsatisfactory. 

In  the  interest  of  systematic  eradication,  it  is  necessary,  espe- 
cially at  the  commencement  of  the  eradication  work,  to  subject  the 
animals  to  the  tuberculin  test  quite  frequently,  with  short  intervals. 

As  a  third  group  Regner  included  436  herds  containing  7,835 
animals  at  the  beginning  of  the  work  and  9,114  cattle  in  1908, 
which  at  the  first  examination,  and  again  in  1908  were  free  from 
reacting  animals. 

The  fourth  group  contains  the  herds  which  originally  were 
free  from  tuberculosis  but  were  not  so  at  the  test  in  1908.  The  98 
herds  included  at  first  2,526  and  in  1908,  3,720  animals,  of  which 
265  or  7.1%  reacted. 

Regner  concludes  from  his  tabulations :  that  on  the  first  tuber- 
culin test  in  1366  herds,  out  of  49,112  animals  tested,  14,175  or 
28.9%  reacted;  that  in  1909  the  same  herds  contained  57,734  ani- 
mals, of  which  1761,  or  3.1%  reacted;  that  Bang's  method  is  the 
strongest  factor  in  the  general  promotion  of  breeding,  and  of 
stable  and  milk  hygiene. 

In  other  countries  the  results  were  similarly  favorable. 

Bang  succeeded  in  Denmark,  from  1893  to  1908,  in  gradually 
reducing  the  percentage  of  reacting  animals  from  40  to  8 . 5.  Malm 
in  Norway  from  1896  to  1903  reduced  the  disease  from  8.4  to 
4.9%.  Hojer  in  Finland  in  1894  to  1900  caused  the  infection  to 
drop  from  24  to  10.1%. 

Hutyra  reports  on  experiments  carried  out  on  the  government 
farm  of  Mezohegyes.  In  this  herd  the  first  tuberculin  test  in  1898 
showed  44.8%  of  reactors  out  of  329  cows  or  26.6%  of  the  entire 
herd  (647  animals),  whereas  in  the  fall  of  1903  out  of  502  cows  only 
2.8%,  and  out  of  the  total  of  1,132  animals  only  1.8%  reacted  to  the 
tuberculin  test.  The  herd  had  been  increased  in  this  period  by 
75%,  without  purchasing  additions  to  it,  and  the  percentage  of 
reactions  had  dropped  88%. 

The  stringent  measures  of  Bang  have  been  somewhat  modi- 
fied in  certain  cases  for  economic  reasons,  or  when  the  strict  execu- 
tion of  Bang's  method  has  presented  peculiar  difficulties.  On  the 


Ostertag's  Method. 


other  hand  the  requirements  have  been  accentuated  in  cases  where 
favorable  considerations  prevailed.  Thus  for  instance  in  a  herd  in 
which  only  a  few  animals  react  it  would  be  advisable  to  dispose  of 
them  without  further  consideration,  and  after  a  thorough  disinfec- 
tion of  the  stable  the  defensive  work  against  tuberculosis  may  be 
instituted,  through  the  introduction  of  only  non-reacting  cattle, 
and  by  the  disposing  of  all  animals  which  prove  tuberculous  on 
the  following  tuberculin  tests. 

The  Siedamgrotzky-Ostertag  method  consists  of  immediate 
disposition  of  all  animals  with  open  tuberculosis  (by  this  means 
the  animals  eliminating  tubercle  bacilli  are  excluded),  and  in 
bringing  up  the  calves  free  of  tuberculosis  by  feeding  them  with 
pasteurized  milk  or  with  milk  from  healthy  cows.  The  calves  are 
subjected  to  the  tuberculin  test  after  they  are  weaned,  and  the  re- 
acting animals  are  not  bred.  The  herds  which  are  included  in  this 
method  of  eradication  are  subjected  semi-annually  to  a  clinical 
examination,  and  the  clinically  suspected  animals  are  removed  and 
disposed  of.  Further  than  this,  the  mixed  milk  of  the  herd,  as  well 
as  the  suspicious  secretions  and  excretions  are  examined 
bacteriologically. 

The  results  of  the  Ostertag  eradication  method  of  course  can 
not  be  compared  with  that  of  Bang.  Since  there  are  retained  in 
the  herd  all  tuberculous  animals  which  show  no  clinical  form  of 
tuberculosis,  or  in  which  there  is  a  suspicion  of  open  tuberculosis 
but  whose  secretions  and  excretions  fail  to  reveal  the  presence  of 
tubercle  bacilli.  Therefore  a  constant  danger  of  infection  for  the 
animals  free  of  the  disease  prevails,  as  tuberculosis  may  at  any 
time  develop  into  an  open  form.  But  since  it  is  required  that  the 
calves  should  be  brought  up  free  of  tuberculosis,  and  that  the  elim- 
inators of  tubercle  bacilli  should  be  determined  by  periodical  clin- 
ical examinations  as  well  as  by  the  testing  of  the  entire  mixed  milk 
of  the  herd  and  the  individual  secretions  and  excretions  of  sus- 
pected animals,  Ostertag  has  obtained  relatively  very  good  results, 
where  his  requirements  have  been  conscientiously  carried  out. 

This  method  has  an  advantage  in  that  the  stock  owners  who 
offer  great  objections  to  radical  methods  of  eradication  on  ac- 
count of  the  immediate  economic  losses  which  they  entail,  are  will- 
ing to  work  intelligently  and  with  pleasure  with  a  system  of  eradi- 
cation such  as  is  offered  by  Ostertag's  method. 

This  assertion  is  best  proven  by  the  tabulation  of  Bautmann,  which  shows  the  in- 
creasing popularity  of  this  method.  The  method  was  voluntarily  adopted  in  the  fol- 
lowing cases: 

1903-1904,   1,457  animals;    1904-1905,   1,372;    1905-1906,  5,333;    1906-1907,  5,395; 
1907-1908,  5.193;   1908-1909,  8,839;   1909-1910,  18,822;   and   1910-1911,  19,828   animals. 
The  following  data  illustrate  the  results  obtained  with  the  method: 
Open  tuberculosis  was  present  in  the  province  of: 

East  Prussia n  1900      in  2.7  %  out  of  10900  examinations 

East  Prussia     ;  •  n  1904      in  1.3  %  out  of  17500  examinations 

Pommerania  n  1902      in  2.93%  out  of     8808  examinations 

Pommerania  n  1906      in  0.6  %  out  of  22356  examinations 

Brandenburg        m  1903      in  3.46%  out  of     5200  examinations 


122  Tuberculosis. 


Brandenburg  in  1907  in  1.5  %  out  of  5810  examinations 

Schleswig-Holstein  in  1903  in  2.8.%  out  of  2435  examinations 

Schleswig-Holstein  in  1905-6  in  1.93%  out  of  11000  examinations 

Saxony  in  1903  in  3.6  %  out  of  1457  examinations 

Saxony  in  1906-7  in  2.41%  out  of  5395  examinations 

In  these  statistics  it  should  be  considered  that  every  year  new,  unexamined  herds 

have  been  included,  and  further  that  the  experts  continually  gained  more  skill  in  making 

the  examination. 

A  proof  of  the  reduction  of  tlie  dangerous  forms  of  tuber- 
culosis is  first  of  all  indicated  by  the  above  figures,  and  also  by  the 
marked  reduction  of  tuberculosis  of  hogs.  Thus  for  instance  ac- 
cording to  Stier  the  percentage  of  tuberculous  creamery  hogs  which 
amounted  to  40%  was  reduced  to  4%  after  the  elimination  of  six 
cattle  with  tuberculosis  of  the  udder,  although  none  of  the 
skimmed  milk  fed  to  the  hogs  had  been  sterilized. 

In  1907  out  of  38,454  animals  examined  in  Schleswig,  1.4% 
were  found  to  be  affected  with  pulmonary  and  udder  tuberculosis. 
Udder  tuberculosis  alone  was  demonstrated  in  0.124%.  In  spite 
of  the  great  advantages  of  the  method,  the  results  eventually  come 
to  a  standstill,  as  may  be  seen  from  the  more  recent  reports  of  the 
eradication  stations.  The  number  of  the  dangerous  forms  cannot 
be  reduced  below  a  certain  percentage,  since  latent  forms  contin- 
uously change  into  the  dangerous  forms,  and  it  is  therefore  im- 
possible to  eliminate  the  sources  of  infection  from  the  herds. 

The  method  of  Ujhelyi  also  deserves  mention.  In  this  method  the  cattle  are  divided 
into  a  healthy  herd  and  those  which  react  to  tuberculin.  The  newly  born  animals  of 
the  group  giving  a  positive  tuberculin  reaction  are  allowed  to  remain  only  in  emergency 
cases  with  the  reacting  mothers,  but  if  possible  they  are  nursed  by  healthy  cows. 

After  weaning  the  calves  are  tested  with  tuberculin.  This  method  differs  from 
Bang's  method  only  in  that  sterilized  milk  is  not  used  (prevention  of  calf  diarrhea)  and 
further  the  calves  are  allowed  at  times  to  remain  with  the  reacting  cows.  According  to 
Ujhelyi 's  report  this  method  has  given  irreproachable  results.  It  has  to  be  considered 
however  that  of  the  weaned  calves  a  greater  proportion  of  animals  must  be  eliminated 
when  this  method  is  employed,  than  when  Bang's  method  is  followed. 

Before  the  introduction  of  Ujhelyi 's  method,  out  of  1,031  adult  cattle,  884,  or 
85.7%  reacted.  Out  of  626  young  stock  333,  or  53.2%  reacted.  After  a  period  of 
eradication  for  4%  years  Ujhelyi  succeeded  in  reducing  the  infection  to  4.1%  among 
the  adults,  and  2.6%  in  the  young  stock.  He  succeeded  in  the  periods  from  1898  to  1902, 
and  from  1904  to  1905,  in  reducing  the  number  of  positive  reactions  among  1,715  cattle, 
of  eight  state  farms,  from  59%  to  3%. 

The  eradication  of  tuberculosis  has  been  .subjected  to  official 
control  for  several  years  in  Denmark,  Sweden,  Norway  and  Fin- 
land. Thus  Denmark  in  1893  contributed  $13,500.00,  later  $27,-- 
000.00  towards  the  eradication  of  tuberculosis,  furnished  the  tuber- 
culin free  of  charge  at  first  for  young  animals,  later  for  adults,  and 
finally  since  1898  took  upon  itself  the  total  expenses  of  eradication 
(Hutyra).  The  skimmed  milk  is  permitted  to  be  returned  from 
the  creameries  to  the  stock  owners  only  after  being  heated  to  80 
deg.  C.  Cows  affected  with  tuberculosis  of  the  udcler  are  destroyed, 
the  owners  being  reimbursed.  There  are  about  600  such  animals 
paid  for  annually. 

Similar  results  were  obtained  in  Sweden,  which  adopted  legis- 
lative measures  and  made  a  contribution  of  $225,000.00.  In  the 


Results   of   Control   Work. 


years  from  1897  to  1908  in  1,370  herds  with  48,576  animals,  of 
which  14,225  or  29.3%  reacted,  the  amount  of  infection  was  re- 
duced by  their  work  of  eradication  to  such  an  extent  that  out  of 
57,660  cattle  only  3.1%,  that  is  1,765  animals,  reacted. 

Although  the  statistics  of  individual  countries  having  strict 
measures  of  eradication  (Denmark,  Sweden,  etc.)  appear  to  show 
the  splendid  effects  of  carefully  executed  control  work,  based  on 
scientific  principles,  and  in  spite  of  the  fact  that  the  milder  modifi- 
cations, as  for  instance  that  of  Ostertag,  by  no  means  show  the 
same  good  results,  nevertheless  measures  of  too  strict  requirements 
cannot  be  absolutely  approved. 

Thus  for  instance  Belgium  in  1895  required  the  destruction  within  a  certain  time 
of  all  clinically  affected  and  all  reacting  animals,  and  in  1896  out  of  19,004  cattle 
examined  9,280  were  slaughtered.  The  difficulty  of  the  execution  was  lessened  by  the 
law  of  1897  which  required  that  only  the  visibly  affected  animals  should  be  destroyed, 
a  measure  which  resulted  in  the  destruction  of  10,269  cattle  with  reimbursement 
amounting  to  $300,000.00,  in  1902  (Hutyra  and  Marek). 

Theoretically,  the  most  radical  eradication  measures  may  pos- 
sibly be  considered  as  the  quickest  and  most  effective,  and  therefore 
from  an  economic  standpoint  as  the  best  methods  for  the  control 
of  tuberculosis.  Owing  to  the  extraordinary  spread  of  this  dis- 
ease in  almost  all  herds,  drastic  measures  however  may  result  in 
the  sudden  infliction  of  such  heavy  economic  losses,  not  alone 
through  the  animals  destroyed,  but  through  changes  of  values  for 
breeding,  dairy  purposes,  meat  production,  etc.,  that  the  stock 
owners,  dealers,  consumers,  etc.,  would  have  good  grounds  to  pro- 
test against  the  execution  of  such  methods. 

Therefore  it  is  advisable  to  adopt  Ostertag's  method  at  the  ini- 
tiation of  the  general  work  of  eradication,  and  after  the  stock  own- 
ers have  been  convinced  that  the  idea  is  rational  following  the 
favorable  practical  results  obtained,  then  Bang's  method  may  be 
introduced,  unless  it  is  possible  to  persuade  them  to  employ,  at  the 
beginning,  the  rational  execution  of  Bang's  method.  In  no  instance 
however  should  destruction  of  the  reacting  animals  be  required 
in  connection  with  Bang's  method.  From  the  standpoint  of  milk 
hygiene  it  does  not  seem  to  be  justifiable,  according  to  the  present 
status  of  the  question  of  the  infectiousness  of  the  milk  of  reacting 
animals,  to  require  their  exclusion  from  the  production  of  milk, 
unless  they  show  clinical  evidence  of  the  disease. 

In  spite  of  the  separation  of  the  reacting  from  the  non-react- 
ing animals,  the  milk  of  the  reacting  group  could  be  marketed, 
from  the  standpoint  of  milk  hygiene,  with  the  milk  of  the  other 
group,  without  interference,  as  has  been  previously  practiced,  so 
long  as  there  is  no  substantial  proof  offered  as  to  the  danger  of 
marketing  such  milk. 

With  the  new  law  on  diseases  of  animals  the  initiation  of 
eradication,  based  on  uniform  legislative  measures,  has  been  in- 
stituted in  Germany,  and  thereby  serves  as  a  stimulus  to  extensive 
private  activity  in  matters  of  eradication. 


124  Tuberculosis. 


The  law  requires  that  clinically  affected  tuberculous  animals, 
or  those  in  which  tuberculosis  probably  exists  to  a  great  extent, 
may  be  ordered  destroyed  by  the  police  authorities. 

If  this  is  not  carried  out,  or  if  the  destruction  is  postponed, 
sanitary  police  protective  measures  should  be  inaugurated  against 
further  spread  of  the  disease,  by  branding  the  animals. 

The  police  measures  against  the  spread  of  the  disease  con- 
sist in  separation,  observation  of  police  control  of  the  affected,  sus- 
pected and  susceptible  animals;  if  necessary  restriction  of  traffic 
of  both  man  and  animals,  and  special  limitations  relative  to  the  use 
of  affected  or  suspected  animals,  and  their  carcasses,  and  finally  the 
usual  requirements  of  disinfection. 

For  animals  which  are  destroyed  by  the  requirements  of  the 
police,  and  those  which  after  destruction  has  been  ordered,  die  of 
the  disease  on  account  of  which  they  had  been  ordered  destroyed, 
the  government  allows  corresponding  reimbursement. 

Of  great  importance  in  tuberculosis  eradication  is  the  require- 
ment prohibiting  the  return  of  skimmed  milk  and  other  milk  residue 
to  the  milk  producers,  as  food  for  other  animals,  unless  the  same 
has  been  heated. 

This  clause  is  included  in  the  general  requirements  of  the 
measure.  Centrifugal  slime,  which  has  formerly  caused  the 
development  of  ingestion  tuberculosis  in  hogs,  must  be  destroyed 
by  burning  or  burying. 

The  measures  differentiate  three  danger  classes  in  tuberculo- 
sis: (1)  the  simple  suspicion,  (2)  the  great  probability  of  its 
presence,  and  (3)  the  actual  existence  of  the  disease.  In  the  pres- 
ence of  the  clinically  recognizable  classes  of  tuberculosis,  it  is 
required  that  the  milk  from  such  affected  animals  should  not  be 
sold  or  otherwise  utilized  without  being  previously  subjected  to  a 
required  temperature  for  a  certain  length  of  time. 

The  milk  from  cows  affected  with  tuberculosis  of  the  udder 
cannot  be  used  for  human  consumption  even  after  subjecting  it  to 
the  required  heat,  nor  can  it  be  utilized  for  the  preparation  of  dairy 
products. 

The  requirements  in  Bavaria  order  the  destruction  of  an  ani- 
mal only  when  it  belongs  to  a  herd  in  which  cattle  breeding,  or 
raising  of  cattle  is  industrially  followed,  and  an  appropriate  volun- 
tary method  of  eradication  of  cattle  tuberculosis  may  then  be 
carried  out  in  the  herd  under  veterinary  supervision. 

This  ought  to  result  in  a  considerable  improvement  of  the  tu- 
berculosis question,  and  with  the  elimination  of  animals  which  prin- 
cipally enter  into  consideration  as  distributors  of  bacilli,  a  point 
is  gained  which  temporarily  should  thoroughly  satisfy  even  the 
milk  hygienists. 

With  such  measures  the  stock  owner  is  pleased,  as  the  pro- 
fessional direction  of  rational  breeding  in  connection  with  eradica- 
tion is  shown  to  be  for  his  advantage.  This  constitutes  the  basis 


Bacillus  Pyogenes. 


on  which  the  entire  milk  production  in  all  its  relations  may  be  ele- 
vated, and  will  be  elevated,  since  the  voluntary  intelligent  co-opera- 
tion of  the  owners  constitutes  the  fundamental  principle  on  which 
the  state  bases  its  allowance  of  reimbursement. 

Without  the  voluntary  co-operation  of  the  producers,  the 
elevation  of  milk  hygiene  is  practically  impossible. 

It  will  take  years  before  the  conditions  will  markedly  improve, 
but  the  improvements  will  surely  come,  and  they  will  not  confine 
themselves  alone  to  the  tuberculosis  question. 

Other  Forms  of  Mastitis. 

The  other  forms  of  chronic  mastitis,  with  the  exception  of 
tuberculosis  of  the  udder,  are  of  slight  importance  for  practical 
purposes  when  compared  with  streptococcic  mastitis. 

Thus  for  instance  the  mastitis  produced  by  the  Bacillus  pyog- 
enes  bovis  is  relatively  rare,  and  the  author  has  had  the  oppor- 
tunity on  only  three  occasions  to  attribute  the  development  of 
chronic  mastitis  to  the  Bacillus  pyogenes.  Glage,  Nielsen,  Kuhl- 
mann,  and  Sven  Wall,  however,  have  observed  the  infection  fre- 
quently, and  even  describe  an  epizootic  extension  of  the  infection. 
Mixed  infections  of  staphylococci  and  colon  bacteria,  with  the 
Bacillus  pyogenes,  appear  to  be  more  frequent  and  in  these  cases 
a  severe  mastitis  is  produced.  It  results  in  abscess  formation  and 
necrosis  of  the  affected  parts,  with  an  induration  of  the  tissues. 
The  secretion  is  sanio-purulent,  and  mostly  of  an  offensive  odor. 
Kiinnemann  found  the  bacillus  at  first  in  suppurations  of  cattle, 
and  Grips  in  suppurating  processes  of  hogs.  They  are  small,  deli- 
cate rods  of  the  size  of  the  swine  erysipelas  bacillus,  growing  bet- 
ter anaerobically  than  aerobically,  forming  dew-drop  like  colonies 
on  agar,  or  serum  agar.  Milk  coagulates  to  a  uniform  clot.  The 
bacillus  does  not  take  the  Gram  stain,  but  it  may  be  stained  by 
Weigert's  method. 

Very  little  is  known  relative  to  the  behavior  of  the  Bacillus 
pyogenes  bovis  towards  man.  According  to  the  author's  observa- 
tions it  appears  to  belong  to  the  group  of  pseudo-influenza  bacilli 
(Pfeiffer).  Such  rods  were  found  in  influenza-like  pneumonias,  in 
bronchitis  (Pfeiffer),  in  suppuration  of  the  middle  ear  (Kossel, 
Hartmann,  Pielicke  and  Cantani),  also  in  whooping  cough  (Afan- 
asieff,  Szewetschenko,  Wendt  and  others).  Friedberger  discovered 
a  similar  rod  in  the  mucus  of  the  prepuce  of  a  dog.  Frank 
describes  it  in  the  pus  of  a  hog.  Frosch  found  it  in  the  blood  of 
geese,  and  Beck  in  an  infectious  pneumonia  of  rabbits.  It  belongs 
to  a  widely  spread  bacterial  group. 

The  Bacillus  pyogenes  is  non-pathogenic  for  small,  experimen- 
tal animals  and  pigeons. 

Since  rods  similar  to  those  of  the  Bacillus  pyogenes  have  been 
found  in  man  it  is  not  impossible  that  affections  of  man  may  be 
produced  by  milk  from  udders  with  this  form  of  infection. 


126 


Mastitis. 


It  has  not  yet  been  possible  to  demonstrate  this  bacillus  in 
mixed  milk,  since  there  occur  too  many  bacteria  of  similar  mor- 
phology in  stable  manure,  in  the  air,  and  under  the  epithelia  of  the 
teats. 

At  any  rate  the  milk  must  be  considered  as  spoiled  when  it 
contains  secretion  from  udders  with  pyogenic  infections,  and  should 
be  excluded  from  the  market,  since  its  injurious  effects  upon  health 
seem  to  have  been  demonstrated  in  the  sense  of  the  pure  food  act. 

Infections  with  bacteria  of  the  coli-typhus  group  frequently 
occur  when  the  cows  are  kept  in  filthy  condition,  with  unclean  bed- 
ding, and  also  when  manipulations  are  undertaken  by  milkers  in 
order  to  dilate  the  milk  ducts  (penetration  with  straws,  quills,  and 


CHiltures   of  Bacillus  paratyphus.      1  X  800.      (After  Kitt.) 

contaminated  milking  tubes).  Representatives  of  this  group  of 
organisms  were  described  by  Jensen  and  Streit,  Guillebeau,  Kitt, 
Freudenreich,  Lucet,  Sven  Wall  and  Weicliel,  as  the  cause  of  high- 
ly acute  forms  of  mastitis.  The  bacteria  are  short  rods  with  round- 
ed ends,  mostly  motile;  they  do  not  take  Gram's  stain.  Accord- 
ing to  their  biologic  characteristics  various  varieties  may  be  dis- 
tinguished, which  at  times  approach  more  closely  to  the  colon 
group,  at  other  times  more  to  the  aerogenes  group,  and  at  times  even 
to  the  enteritidis  group,  which  cause  meat  poisoning. 

Milk  becomes  coagulated  with  gas  formation.  The  acidification  and  coagulation 
occur  earlier  with  some  varieties  than  with  others.  The  colon  group  always  ferments 
galactose,  glucose,  laevulose,  mannose,  lactose,  maltose,  arabinose,  rhamnose,  xylose, 
mannit  and  sorbit,  frequently  also  sorbose,  saccharose,  raffinose  and  dulzit,  but  not 


Causes  of  Mastitis. 


erythrit  and  adonit.  Their  action  is  different  towards  saccharose,  raffinofe,  sorbose  and 
dulzit,  and  this  differentiation  is  utilized  to  separate  the  groups  into  those  which  do  not 
attack  any  of  the  mentioned  bodies,  those  which  ferment  all  four,  those  which  split  up 
dub  it  and  sorbose,  and  finally  those  splitting  up  saccharose  and  raffinose.  Of  course 
bacteria  cannot  be  strictly  separated  by  their  fermentative  action,  since  in  the  cultivation 
of  colon  strains  in  sugar-containing  media  they  may  acquire  the  faculty  of  fermenting  a 
kind  of  sugar  towards  which  they  formerly  were  refractory  (Twort,  Massini).  Through 
the  first  group  the  colon  bacteria  approach  the  more  dangerous  group  of  Bacillus  para- 
typhus  B.,  Bacillus  enteritidis  of  Gartner  and  paracolon  bacteria  with  their  related 
organisms,  for  instance  the  Bacillus  raiin.  Bacillus  suipesiifer,  B.  typhi  murium,  etc. 
These  dangerous  groups  may  be  separated  by  agglutination  into  three  classes,  the 
Bacillus  enteriiidis  Gartner  group,  the  Bacillus  paratyphus  B.  group,  and  finally  the 
Paracolon  group. 

Weichel  succeeded  in  isolating  from  two  cases  of  severe  sep- 
tic mastitis  an  organism  belonging  to  the  group  of  Bacillus  enteri- 
tidis, and  another  to  the  Bacillus  paratyplius-B. 

Excluding  the  inflammatory  products  which  may  also  possess 
disease-producing  properties  in  this  group  of  mastitis  forms,  it  is 
necessary  to  exercise  special  care  in  the  inflammations  of  the  ud- 
der caused  by  the  Coli-eiiteritidis-paratyplius-paracoli  organisms, 
since  among  the  representatives  of  this  group  of  bacteria  there  are 
those  which  may  produce  severe  forms  of  enteritis  in  man,  with 
symptoms  of  poisoning,  which  are  known  in  general  as  meat  poi- 
soning. True  paratyphus  bacteria  may  also  enter  the  milk  in  other 
ways  than  with  the  secretion  of  an  infected  quarter,  for  instance 
through  bacilli-carriers  who  are  employed  for  handling  the  milk, 
through  the  rinsing  water,  and  also  from  other  sources.  It  will  be 
of  interest  to  mention  here  the  results  of  examinations  of  market 
milk  for  the  occurrence  of  Bacillus  paratyphus-B. 

Uhlenhuth  and  Hiibener  twice  found  paratyphus  in  100  sam- 
y>les,  while  Hiibener  in  40  samples  of  market  milk  noted  this  bacil- 
lus 4  times  and  in  30  other  samples  of  market  milk,  observed  it 
3  times. 

Klein  in  39  mixed  milk  samples  found  the  Bacillus  enteritidis 
9  times. 

The  occurrence  of  coli-aerogenes  bacteria  in  milk  would  be 
something  very  ordinary,  and  would  be  considered  less  injurious 
for  the  health  than  the  presence  of  varieties  which  are  known  as 
toxin  producers. 

Nevertheless  the  coli-aerogenes  infections  of  the  udder  should 
be  considered  with  the  greatest  care ;  although  in  general  the  enter- 
itidis and  paratyphus  varieties  produce  severe  septic  inflammations 
with  ichorous  secretions  and  frequently  with  a  fatal  termination, 
the  severity  of  mastitis  and  the  appearance  of  the  secretion  are  by 
no  means  a  certain  indication  of  the  character  of  the  infection. 

Mixed  milk  to  which  the  secretion  from  animals  with  acute  af- 
fections of  the  udder  has  been  added,  is  spoiled  according  to  the 
pure  food  act,  and  should  be  considered  as  capable  of  injuring 
human  health. 

The  milk  of  healthy  quarters  from  such  infected  udders  is  also 


128  Mastitis. 

suspicious  of  being  contaminated  with  the  infective  agents,  and 
therefore  should  be  prohibited  from  entering  the  market. 

According  to  Weichel  reports  on  paratyphus  and  enteritidis 
infections  which  may  be  traced  to  milk  are  rare,  and  no  publications 
can  be  found  which  absolutely  trace  affections  in  man  to  a  coli- 
paratyphus  mastitis. 

The  Dairy  Journal  of  Berlin  reported  in  1900  that  according  to  "Dag.  Nyheter" 
nine  families  in  Stockholm  became  affected  with  symptoms  of  meat  poisoning  (fever, 
depression,  fainting  spells,  nausea,  vomiting,  diarrhea,  muscular  cramps).  The  milk,  to 
the  consumption  of  which  the  affection  was  traced,  originated  from  14  cows,  one  of 
which  suffered  from  an  inflammation  of  the  udder.  In  the  secretion  of  the  affected 
udder  the  same  bacteria  were  found  as  in  the  feces  of  the  affected  people. 

Two  female  attendants  of  the  stable  from  which  the  injurious  milk  was  obtained  also 
became  affected  with  similar  symptoms. 

The  observation  of  Moro  also  belongs  here.  Moro  observed  in  six  persons  after  the 
consumption  of  milk  from  a  goat  suffering  with  a  gangrenous  inflammation  of  the 
udder,  chills,  nausea,  headaches,  and  11  hours  later  colic,  vomiting  and  thirst.  The 
milk  was  consumed  mixed  with  coffee. 

Weigmann  and  Gruber  report  a  case  of  injurious  effect  (vomiting),  from  cream 
which  had  been  prepared  from  mastitis  milk,  and  they  traced  the  affection  to  a  bacillus 
of  the  colon  group  (immobilis). 

Weichel  fed  a  six-weeks  old  dog  with  the  milk  of  a  goat  which  was  artifically 
infected  in  the  udder  with  a  paratyphus  strain  from  septic  mastitis.  The  feeding  was 
undertaken  after  the  appearance  of  the  mastitis  in  the  goat.  Three  hours  after  the 
consumption  of  200  c.  c.  of  the  secretion  the  dog  showed  marked  symptoms  of  restlessness 
and  barked  frequently;  lachrymation  and  later  repeated  vomiting  appeared.  He  soon 
recovered  but  refused  to  partake  again  of  this  milk. 

Only  after  60  c.  c.  of  this  fluid  had  been  mixed  with  200  c.  c.  of  good  milk  would 
he  touch  it ;  he  then  took  a  small  quantity  but  with  apparent  distaste.  Within  five  minutes 
he  showed  pain,  and  manifested  similar  symptoms  as  the  day  before,  but  again  recovered 
before  the  following  day. 

In  a  second  feeding  experiment  on  a  seven-weeks  old  dachshund  the  affection 
commenced  only  on  the  fifth  day  of  the  experiment.  The  animal  became  listless,  refused 
food,  whined,  and  in  addition  lachrymation,  nasal  discharge,  and  periodical  chills 
appeared.  This  dog  also  recovered  on  the  second  day. 

Weichel  also  reports  a  case  in  which  the  wife  and  daughter  of  a 
dairyman  became  affected  with  a  diarrhea  after  the  ingestion  of 
inflammatory  products  of  a  cow  with  coli-mastitis.  The  dog  of  the 
owner  also  showed  similar  symptoms  after  drinking  the  milk. 

As  milk  offers  very  favorable  conditions  for  the  multiplication 
of  bacteria  of  this  group,  the  danger  from  milk  containing  coli- 
paratyphus  bacteria  must  be  considered  greater  than  in  the  case 
of  meat  bearing  the  same  infection.  Various  data  exist  relative  to 
the  resistance  of  these  bacteria  towards  influences  of  heat. 

According  to  Fischer  heating  to  60  desr.  C.  for  a  half  hour  does 
not  suffice  to  kill  all  paratyphus  germs ;  likewise  some  of  the  bac- 
teria remained  active  after  heating  the  milk  for  10  to  35  minutes  at 
70  deg.  or  for  five  minutes  at  75  deg.  C. 

Although  Kolle  states  that  the  typhoid,  paratyphoid,  and 
enteritidis  bacteria  are  without  exception  destroyed  when  sub- 
jected to  a  temperature  of  59  deg.  C.  for  10  minutes,  nevertheless  it 
must  be  remembered  that  the  conditions  in  milk  are  markedly  dif- 
ferent than  in  suspensions  of  culture,  and  that  some  of  the  varieties 
are  capable  of  producing  a  heat-resisting  toxin.  According  to  Gart- 
ner the  toxins  of  the  meat-poisoning  organisms  withstand  100  and 


Mixed  Infections  of  Udder. 


even  120  deg.  C.  These  facts  were  confirmed  by  Van  Ermengem, 
Drigalski,  Fischer,  Hoffmann,  Peels,  Hoist,  Dhant,  Riemer,  and 
others. 

In  practice  therefore  it  is  necessary  to  consider  the  mixed  milk 
of  the  affected  cow  and  all  dairy  milk  to  which  such  milk  has  been 
added  as  injurious  to  health,  whenever  it  is  proven  with  certainty 
that  it  contains  secretion  from  acutely  affected  quarters. 

If  it  is  proven  with  certainty  that  the  secretion  contained  bac- 
teria of  the  paratyphoid  or  enteritidis  group  such  milk  may  even 
destroy  human  health. 

Of  course  the  danger  which  threatens  man  from  such  milk 
must  not  be  overestimated.  The  changes  in  the  udder  and  in  the 
milk  are  pronounced  and  striking,  and  usually  appear  very  sudden- 
ly, especially  in  the  colon  inflammations,  somewhat  less  in  para- 
typhoid and  enteritidis  infections.  Nevertheless  in  the  presence 
of  carelessness  of  the  milker  such  infections  may  enter  the  milk. 

According  to  Fauss  the  duration  of  the  elimination  of  the 
bacteria  from  affected  udders  persists  for  12  to  30  days,  in  fatal 
cases  until  death.  The  number  of  the  eliminated  bacteria  and  the 
duration  of  the  elimination  are  proportional  to  the  severity  of  the 
case,  and  they  cease  when  the  milk  again  approaches  its  normal 
condition. 

In  other  cases  of  acute  mastitis  staphylococci  have  been  dem- 
onstrated. Guillebeau  isolated  the  Stapliylococcus  mastitidis, 
Galactococcus  versicolor,  Galactococcus  fulvus,  and  Galactococcus 
albus.  Experimentally  it  is  also  possible,  as  proven  by  Kitt  with 
the  Botryococcus  ascoformans  (a  staphylococcus),  to  produce  an 
acute  mastitis,  with  a  tendency  to  chronic  development. 

The  staphylococci  infections  of  the  parenchyma  of  the  udder 
are  relatively  rare,  but  occur  more  frequently  as  mixed  infections 
with  the  Bacillus  pyogenes.  While  the  course  of  the  staphylomyco- 
sis  of  the  udder  is  mostly  acute,  with  a  favorable  progno- 
sis, yet  in  the  presence  of  a  mixed  infection  with  the  Bacillus  pyog- 
enes it  frequently  results  in  abscess  formation  and  sequestration 
of  the  udder. 

The  staphylococci  are  small  round  microbes,  separated  into 
two  or  four  parts  by  division.  They  take  the  Gram  staining.  They 
are  easily  cultivated  on  all  media  and  are  frequently  chromogenic. 
They  liquefy  gelatin  from  the  surface  down,  since  they  grow  better 
aerobically  than  anaerobically. 

Staphylococci  corresponding  to  their  ubiquitous  distribution 
are  present  in  almost  all  milk  during  its  first  phases  of  decomposi- 
tion ;  but  although  they  possess  pathogenic  importance  as  pus-pro- 
ducers in  man,  from  the  standpoint  of  market  milk  hygiene,  they 
are  of  no  special  importance  under  such  conditions.  However  when 
the  secretion  of  a  cow  with  staphylomycosis  of  the  udder  contains 
staphylococci,  the  milk  may  be  injurious  to  health.  Karlinski, 
for  instance,  reports  a  case  of  pyemia  in  a  child  in  which  infection 


130  Mastitis. 

resulted  from  the  milk  of  the  mother  containing  staphylococci.  At 
least  the  cocci  which  Karlinski  isolated  from  the  milk,  and  from 
f eces  and  blood  from  the  child  were  identical.  The  secretion  there- 
fore must  be  considered  as  spoiled  food,  and  must  be  excluded  from 
consumption. 

The  same  judgment  as  stated  for  staphylococci  infections  also 
applies  to  botryomycosis  of  the  udder.  This  represents  a  chronic 
form  of  a  staphylomycosis,  in  which  the  single  cocci  that  grow 
in  colonies  are  compressed  by  swelling  of  the  cocci  lying  on  the  out- 
er borders,  forming  capsulated  spherical  colonies.  The  central 
cocci  continue  to  grow,  burst  the  capsules,  and  the  process  of  the 
swelling  of  the  bordering  zone  is  renewed  until  mulberry-like  fun- 
goid colonies  result.  A  method  of  distinguishing  Botryococcus 
ascoformans  from  staphylococci  has  not  yet  been  devised.  The 
botryomycotic  formations  develop  mostly  in  the  horse  which  is 
probably  proof  of  certain  immunity  strength  of  the  horse  (that  is 
of  equidia),  against  staphylococci  infections.  In  other  animals  and 
also  in  cattle  the  disease  is  extremely  rare.  Mohler,  Czokov,  Immel- 
mann,  and  Eeinhardt  have  observed  botryomycosis  in  the  udder 
of  cows.  Botryomycosis  in  cattle  is  of  no  practical  inportance  in 
the  judgment  of  milk. 

Actinomycosis  of  the  udder  is  also  of  slight  importance  from 
a  practical  standpoint. 

The  purulent  fibroplastic  actinomycotic  mastitis  occurs  in 
cattle  with  less  frequency  than  the  actinomycosis  of  other  organs. 
It  has  been  described  by  Kasmussen  (four  times),  Jensen  (20 
times),  Maxwell  (once),  Bang,  and  Johne,  and  represents  a  chronic 
suppuration  with  nodular  cicatrization  of  the  udder.  After  the  in- 
fection, nodules  from  a  bean  to  a  hen's  egg  in  size,  with  softened 
centers  and  fibrous  borders  develop,  or  a  diffuse  inflammation  with 
a  tendency  toward  cicatrization  and  hardening  of  the  entire  udder 
results.  Actinomycosis  of  the  udder  may  be  primary  (McPhail, 
Williamson)  and  develop  from  the  introduction  of  barley  beards 
into  the  tissue,  or  possibly  from  pasturing  on  stubble  fields,  or  again 
it  may  develop  by  metastatic  formations  from  other  lesions  in  the 
body. 

McPhail  believes  that  some  cases  of  so-called  udder  tuberculo- 
sis are  in  reality  actinomycotic  infections  of  the  udder. 

Should  an  actinomycotic  process  soften  in  the  udder  and  the 
abscess  burst  into  the  secreting  tissue,  the  finding  of  actinomyces 
in  the  milk  is  possible.  The  latter  appear  as  colonies  of  ray-like 
fungi  (streptothrix).  The  branching  threads  form  a  mesh-like 
mycelium  with  spherical  or  club-shaped  enlargements  on  the  end  of 
the  threads.  The  fungous  threads  proliferating  in  the  animal 
tissue  are  influenced  by  the  action  of  the  body  fluids.  The  sheaths 
swell  and  club-shaped  bodies  result,  arranged  in  a  radiating  man- 
ner, which  later  become  adherent  to  each  other  forming  rosettes  in 
which  the  mycelium,  protected  from  the  immune  bodies  and  leuco- 
cytes continues  to  proliferate  or  to  degenerate  and  calcify. 


Actinomycosis. 


The  actinomyces  are  widely  spread  forms  of  the  higher  bac- 
teria with  true  branching,  and  stand  between  the  lower  bacteria 
and  hyphomycetes.  They  almost  invariably  occur  on  grain,  hay, 
straw,  fruit,  manure,  soil,  flour  and  milk.  Most  of  the  actinomyces 
are  harmless  provided  a  foreign  body  does  not  facilitate  their  colr 
onization  in  the  animal  body.  Splinters  of  wood,  and  especially 
beards  of  barley  are  frequently  the  carriers  of  the  infection. 

Transmission  from  man  to  man  or  from  animal  to  man  is  not 
known  up  to  the  present  time.  The  basis  of  an  infection  always 
lies  in  wound  infection  either  through  the  above  mentioned  for- 
eign bodies,  or  by  the  fungi  gradually  becoming  accustomed  to  exis- 
tence in  necrotic  tissue  of  the  animal  body  (caries  of  teeth).  Johne 
succeeded  in  producing  actinomycosis  of  the  udder  through  the 
injection  of  actinomycotic  cultures  into  the  milk  cistern. 

Although  transmission  to  man  through  milk  from  actinomy- 
cotic udders  is  not  to  be  feared,  prohibition  of  the  sale  of  such  milk 
is  required  since  it  must  be  considered  as  spoiled  on  account  of 
the  presence  of  pus  and  other  associated  changes. 

Contrary  to  actinomycosis,  "actinobacillosis"  first  described 
by  Lignieres  and  Spitz  in  Argentina,  and  which  clinically  resem- 
bles actinomycosis,  is  of  a  contagious  nature.  Therefore  although 
actinobacillosis  has  not  yet  been  described  in  man  it  should  be  more 
carefully  judged  than  actinomycosis.  In  Germany  cases  of  actin- 
omycosis have  been  reported  which  from  the  bacteriological  find- 
ings, should  be  classed  as  actinobacillosis,  and  these  cases  occur 
sometimes  in  an  enzootic  form  or  as  stable  outbreaks. 

Thus  Imminger  in  Oberpfalz  and  Preusse  in  Western  Prussia, 
described  an  enzootic  extension  of  actinomycosis,  and  Schulze 
mentioned  a  case  in  which  the  disease  affected  most  of  the  animals 
in  the  stable  (of  30  steers  27  were  affected) .  Of  87  newly  purchased 
animals  more  than  half  of  those  placed  in  the  stable  became  af- 
fected, while  12,  which  had  been  stabled  on  other  premises  and 
which  received  the  same  feed,  remained  healthy. 

Milk  from  udders  affected  with  actinobadllosis,  and  mixed 
milk  which  contains  such  secretion  must  be  considered  as  spoiled 
and  prohibited  from  consumption. 

Mixed  infections  of  the  udder  with  these  described  bacteria 
and  others,  should  be  similarly  judged,  and  likewise  infections 
with  malignant  edema  bacteria,  Bacillus  necrophorus,  etc. 


CHAPTER  VII. 

EXTERNAL  INFLUENCES  WHICH  ACT  UPON  MILK. 

(a)  Their  effect  upon  the  body,  thereby  influencing  milk 

secretion ; 

(b)  Their  effect    upon  milk  after  its  secretion. 
Although  our  knowledge,  relative  to  the  development  of  the 

individual  components  of  milk  from  the  substances  in  the  blood, 
scarcely  extends  beyond  the  border  of  hypothesis,  nevertheless  it 
is  established  that  milk  formation  is  dependent  to  a  certain  extent 
upon  the  feeding,  although  only  within  limits  denned  by  the  breed, 
family,  individual,  lactation  period  and  age. 

Through  outside  conditions,  those  factors  of  production  are 
especially  influenced,  which  are  themselves  subject  to  variations, 
especially  the  quantity  of  milk  and  fat  content,  less  so  the  proteid 
and  sugar  content,  and  only  very  slightly  the  salt  content. 

The  influence  of  feeding  could  be  explained  by  reasoning  that 
the  gland  increases  its  activity  at  the  moment  in  which  a  larger 
quantity  of  nutritive  substances  circulates  in  the  blood,  after  the 
ingestion  of  large  quantities  of  easily  digested  food.  This  sup- 
position could  be  even  enlarged  upon  by  considering  that  the  activ- 
ity of  the  cell  is  stimulated  by  specific  substances  in  the  food  in 
such  a  way  that  it  assimilates  to  better  advantage  and  in  increased 
quantities  the  necessary  constituents  which  it  draws  from  the 
blood. 

From  practical  experience  and  scientific  experiments  it  must 
be  considered  as  established  that  the  milk  produced  is  dependent 
both  in  quantity  and  quality,  upon  the  quantity  of  digestible  food 
and  on  the  presence  of  specific  substances  which  stimulate  milk 
formation. 

This  view  has  been  accepted  for  a  long  time  by  practical  dairymen,'  who  for 
instance  have  observed  that  clover  hay,  in  spite  of  its  greater  nutritive  contents  has 
not  come  up  to  the  value  of  good  meadow  hay;  that  meadow  hay  cannot  be  replaced  by 
a  mixture  of  straw  and  concentrated  food  mixed  in  a  way  to  make  its  nutritive  value 
equal  to  the  meadow  hay;  further  that  sweet  hay  proves  a  better  milk  producer  than 
sour  hay  with  equal  nutritive  value,  etc.  The  value  of  individual  pastures  also  shows 
wide  differences  in  the  production  of  milk,  although  examination  of  the  grasses  of  the 
pastures  gives  similar  results.  In  these  investigations  however  it  was  found  that  beyond 
certain  limits  the  influence  of  nutrition  was  no  longer  usable,  and  that  with  sufficient 
feeding  of  wholesome  and  tasty  food  no  influence  could  be  exerted  upon  production 
through  increased  rations. 

132 


Effect  of  Feed  on  Yield.  133 

If  animals  are  allowed  to  starve,  the  change  in  the  quality  of  the 
milk  will  result  only  after  the  reserve  deposits  of  the  body  have 
been  utilized  to  their  fullest  extent,  or  completely  exhausted.  In  the 
state  of  starvation  the  milk  fat  shows  an  approach  in  its  composi- 
tion to  that  of  the  body  fat. 

If  experiments  are  started  with  starving  animals,  or  with 
animals  which  only  receive  small  rations,  the  milk  yield,  according 
to  Kellner,  increases  with  the  added  increase  of  feed.  Such  cows 
after  an  increase  of  rations  yielded: 

With  an  increase  of  1.5  kg.  bean  bran,  the  increase  of  milk 
amounted  to  0.92  and  0.53  kg. 

With  3  kg.  bean  bran,  the  increase  was  2 . 40  and  1 . 01  kg. 

With  1  kg.  malt,  the  increase  was  0.84  and  0.3  kg. 

With  2  kg.  malt  bran,  the  increase  was  1.31  and  0.40  kg. 

The  increase  in  yield  however  was  not  parallel  with  the  in- 
crease of  the  ration,  but  the  closer  the  quantity  of  milk  produced 
approached  the  maximal  production  of  the  individual,  the  slighter 
became  the  increase  in  yield.  In  attempts  to  increase  the  produc- 
tion of  the  cow,  the  last  liter  of  milk  is  the  most  expensive.  It  re- 
quires for  its  production  the  largest  addition  of  rations. 

In  general  it  may  be  said  that  sufficient  quantities  of  digesti- 
ble proteins  are  the  fundamental  requirements  for  normal  milk 
production,  and  that  although  other  food  substances  are  present  in 
sufficient  quantities  the  yield  of  milk  diminishes  rapidly  when  the 
protein  content  is  decreased  below  the  amount  necessary  for  main- 
taining the  body  weight.  For  1000  kg.  of  body  weight  1.212  kg.  of 
digestible  proteins  must  be  figured,  together  with  a  sufficient  addi- 
tion of  fat  and  carbohydrates.  Fat  and  carbohydrates  and  non- 
protein  nitrogenous  substances  in  sufficient  quantities  act  as  econo- 
mizers of  proteins.  For  continuous  milk  production  an  excess  of 
about  0.40  to  0.55  to  0.65  kg.  of  digestible  proteins  is  required 
for  10  kg.  of  milk  (Schmeck  and  Kellner). 

Experiments  of  Morgen  and  Fingerling  proved  that  while 
feeding  tasteless  non-stimulating  food  consisting  of  straw,  cut 
straw,  starch  and  oil,  the  yield  of  milk  may  be  increased  by  the  ad- 
dition of  substances  which  by  themselves  cannot  be  utilized  in  the 
production  of  milk,  and  therefore  they  are  considered  stimulating 
substances  which  principally  stimulate  the  gland  to  activity. 

Increased  Increased 

Addition  yield  yield 

in  milk  in    fat 

Malt  0  gm.  0  gm. 

Buckhorn  seed 10  gm.  0.8  gm. 

Hay  distillate  and  fennel 2.03  gm.  7.9  gm. 

153       gm.  5.6  gm. 

312       gm.  9.8  gm. 

109       gm.  6.7  gm. 

The  percentage  of  fat  increased  0.25  to  0.32%. 


134  Effect  of  External  Influences. 

In  order  to  produce  an  increase  of  milk  it  was  sufficient  to 
introduce  into  the  food  small  amounts  of  fennel,  or  to  sprinkle  it 
with  distillate  of  hay.  If  in  the  experiments  good  meadow  hay  was 
fed  in  sufficient  quantities  with  other  food-stuffs,  the  addition  of 
the  stimulating  substances  was  without  effect.  These  observations 
are  of  special  importance  in  view  of  the  swindles  carried  on  with 
milk  powders,  by  which  money  is  still  extorted  from  the  farmers. 
Through  the  addition  of  salt  to  tasteless  food  an  increased  yield 
in  milk  and  fat  was  obtained  amounting  to  from  20.6  to  21.9%. 

Hansen  reports  on  the  influence  of  concentrated  foods  on 
the  milk  yield,  which  he  investigated  extensively  for  seven  years. 
This  author  divides  the  concentrated  food  into  four  groups : 

1.  Foods  which  increase  the  milk  yield  and  diminish  the 
percentage  of  fat,  as  for  instance  farina,  corn,  oats,  and  possibly 
also  soja  beans. 

2.  Those  which  do  not  influence  the  quantity  of  milk  but 
increase  the  fat  content,  as  for  instance  palm-seed  oil  and  cocoanut 
oil  cakes  (the  specific  action  of  cotton-seed  meal  is  less  pronounced) 
peanut  meal,  corn-slop  and  bread  flour. 

3.  Those  which  do  not  change  the  yield  of  milk  but  reduce 
the  fat  content,  as  for  instance,  poppy  seeds,  flour  of  rice  and  other 
concentrated  food,  beneficial  for  fattening,  as  for  instance  cake  of 
sesame  (Ramm). 

4.  Those  which  have  no  specific  action,  as  for  instance  wheat 
bran,  and  malt  sprouts.     Such  food  substances  are  especially  de- 
sirable for  the  use  of  fattening  dairy  cattle. 

From  the  experiments  of  Hansen  it  appears  as  a  matter  of 
fact,  that  certain  food  substances  possess  a  specific  action.  In 
this  regard  the  composition  of  the  food  is  of  course  of  importance, 
since  the  action  of  a  certain  food  may  be  checked  by  feeding  coun- 
teracting substances.  It  has  long  been  known  from  practical  ex- 
perience that  the  quality  of  milk  may  be  greatly  influenced  through 
the  method  of  feeding,  and  not  only  as  far  as  the  constituents  of 
the  milk  are  concerned  but  also  its  odor,  taste,  etc.  To  what  extent 
food  bacteria  play  a  part  in  this,  will  be  discussed  in  the  chapter 
devoted  to  that  subject. 

Summer  butter,  mountain  butter,  and  stable  butter,  are  richer  in  fatty  acids  with 
low  molecular  weight,  than  fall  butter  or  butter  from  cows  which  have  been  kept  on 
low  land  pastures,  or  pasture  butter  in  general  prepared  in  the  same  manner.  Feed  rich 
in  carbohydrates  produces  a  soft  milk  fat.  If  abnormal  constituents  of  fats  are 
artificially  added  in  experimental  feeding,  or  if  fats  are  fed  which  are  otherwise  not 
found  in  the  body,  such  constituents  are  again  found  in  the  milk,  for  instance  sesame 
oil  (Engel),  linseed  oil,  hemp  seed  oil  (Gogitidse),  iodin  and  iodipin  (Caspari  and 
Winternitz),  Sudan  III,  a  specific  fat  coloring  matter  (Gogitidse). 

According  to  Schrodt  and  Hansen  pasture  milk  on  account  of 
its  greater  contents  of  casein,  contains  more  phosphoric  acid  than 
stable  milk,  which  on  the  other  hand  is  richer  in  chlorin.  Accord- 
ing to  Sanson,  Hesse  and  Schaffer  the  feeding  of  phosphate  also 
increases  the  content  of  phosphoric  acid ;  this  however  according 


Feed  Recommended. 


to  Neumann  is  not  immediate  but  appears  only  after  weeks  and 
then  in  insignificant  proportions.  Jensen  succeeded  in  finding  only 
an  insignificant  influence  on  the  milk  from  the  feeding  of  considera- 
ble amounts  of  lactates  of  iron,  calcium  sulphate,  disodium  phos- 
phate, dicalcium  phosphate,  dimagnesium  phosphate,  potassium 
chloride,  chloride  of  sodium,  and  nitrate  of  potassium.  Nitrates 
appeared  in  the  milk  only  after  75  gm.  of  saltpetre  had  been  fed. 
The  administration  of  from  30  to  40  gm.  of  saltpetre  failed  to  result 
in  the^presence  of  nitrates  in  the  milk.  The  salt  content  of  milk 
therefore  changes  only  insignificantly  provided  normal  conditions 
are  present.  According  to  Henseval  and  Mullie,  the  health  of  the 
animals  plays  a  part  when  salts  pass  into  the  milk.  If  these  authors 
fed  from  5  to  25  gm.  of  saltpetre  to  20  healthy  and  8  diseased 
animals,  the  milk  of  the  sick  animals  always  contained  nitrates, 
whereas  the  milk  of  the  healthy  animals  did  so  only  exceptionally. 
Definite  quantities  of  sulphuric  acid  are  supposed  to  occur  in  milk 
after  the  administration  of  Glauber  salts. 

Of  the  various  foods,  meadow  grass,  green  clover,  rowen, 
green  alfalfa,  and  peas  in  which  a  large  amount  of  young  grain  has 
been  sown  are  recommended,  for  instance,  vetch  with  oats,  barley 
or  rye,  plants  of  the  white  mustard,  rape,  sainfoin,  Kohlrabi  tur- 
nips, etc.,  with  which  oats,  barley  or  rye  have  been  grown.  Fod- 
der or  straw  should  be  mixed  with  the  green  feed.  In  the  winter 
instead  of  green  feed,  mangels,  chopped  roots,  ensilage,  grain, 
potato  slop  and  corn  slop  should  be  fed. 

Relative  to  the  injurious  effects  of  the  various  bacteria  found 
in  feeds  and  pastures,  see  the  chapter  on  milk  abnormalities.  Good 
hay  and  good  fodder  may  be  recommended  as  dry  feed.  As  con- 
centrated food  the  substances  mentioned  by  Hansen  as  indifferent, 
or  those  food  substances  of  the  first  and  second  group  which  are 
recognized  as  milk  and  fat  producers,  will  be  found  satisfactory. 

Rough  fibrous  foods  cause  a  loss  of  energy,  and  are  not  well 
utilized  on  account  of  the  increased  work  of  mastication  and  be- 
cause the  intestines  are  too  greatly  burdened  by  this  feed.  Individ- 
ual feeding  according  to  the  milk  yield  appears  advisable,  and 
the  best  milkers  may  be  allowed  additional  rations  corresponding 
to  their  heavy  production.  In  this  regard  of  course  the  yield  and 
quality  of  the  milk  should  be  established  by  sample  milkings  and 
examination  of  the  secretion.  In  cow-fattening  dairies  the  fatten- 
ing of  the  animals  should  commence  only  in  the  last  three  months 
since  fattening  foods  and  fattening  of  the  animals  diminish  the 
yield  of  the  milk. 

Pure  drinking  water  has  a  great  influence  on  milk  produc- 
tion, and  the  animals  should  be  enabled  to  partake  of  it  freely  ac- 
cording to  their  needs.  Heyken  mentions  a  case  in  which  each  cow 
yielded  one-half  liter  of  milk  per  day  more,  when  instead  of  hard 
marshy  spring  water  containing  iron,  good  well  water  was  sub- 


136  Effect  of  External  Influences. 

stituted.  Backhaus  observed  an  increase  of  milk  and  fat  con- 
tent after  the  introduction  of  an  automatic  water  supply. 

Milk  of  poor  quality  is  known  to  have  resulted  from  the  use 
of  poor  drinking  water.  Stagnant  waters  give  the  milk  a  repulsive 
taste. 

Taken  as  a  whole  all  foods  and  all  food  mixtures  which  are  par- 
taken of  and  digested  by  the  animals  without  disturbance  in  their 
general  condition  are  adapted  to  the  feeding  of  milk  animals.  Food 
which  in  continuous  feeding  causes  diarrhea  or  other  intestinal 
disturbances  should  be  avoided.  Intestinal  disturbances  which 
quickly  subside  and  which  sometimes  develop  as  a  result  of  sudden 
change  of  food  are  of  no  consequence  in  the  judgment  of  the  food. 
They  may  cause  considerable  fluctuation  in  the  yield  of  milk  and 
fat  content,  which  however  subsides  in  a  few  days.  From  the 
above  statement  it  will  be  seen  that  under  certain  conditions,  espe- 
cially when  a  heavy  production  of  cream  is  necessary,  the  effects 
of  a  change  of  food  must  be  considered.  If,  when  considering 
evidence  of  adulteration,  methods  of  examination  are  used  which 
take  note  of  the  approximately  constant  factors  in  milk,  that  is, 
such  as  pertain  to  the  protein-free  milk  serum,  the  influence  of  a 
feeding  method,  or  a  sudden  change  of  feed  should  be  taken  into 
consideration  in  regard  to  its  effect  upon  the  milk  of  each  indi- 
vidual animal. 

Spoiled  food  injures  the  taste  and  odor  of  the  milk  and 
butter,  and  its  effects  may  last  for  a  long  period  after  the  time  of 
feeding  such  food.  The  feeding  of  large  quantities  of  beet  or  tur- 
nip tops  should  be  guarded  against,  likewise  over  feeding  with 
fresh  or  sour  chopped  roots,  potato  slops,  residues  from  starch 
factories,  brewer's  grains,  rape  seed  cake,  flaxseed  meal  and  poor 
straw. 

The  taste  is  improved  by  feeding  on  pasturage,  red  clover, 
meadow  grass,  carrots,  oats  and  rice  flour. 

Firm  tallowy  butter  is  derived  from  grass  of  acid  soil,  from 
grass  from  fall  pastures,  late  hay  made  from  sour  grasses,  leaves 
of  sugar-beets,  or  red  beets,  chopped  roots,  potatoes,  peas,  palm 
seeds,  cocoanut  and  flaxseed  cake,  and  cotton-seed  meal. 

Soft  butter  results  from  the  feeding  of  oat  hulls,  corn  bran, 
wheat  bran,  rice  flour,  rape-seed  cake  and  sunflower-seed  cake. 

Clover  pastures  are  not  suitable  for  the  production  of  milk  for 
cheese  making  since  the  cheese  becomes  permeated  with  small  holes, 
and  has  a  sharp  repulsive  odor.  This  condition  is  probably  brought 
about  by  bacteria  which  vegetate  on  the  clover  plants  of  the 
pasture. 

Changes  from  one  feed  to  another  should  not  be  made  too  sud- 
denly if  it  is  desired  to  prevent  an  effect  on  the  milk  production. 
Newly  introduced  food  substances  should  not  be  fed  in  large 
quantities  at  first.  In  changing  from  dry  food  to  pastures  a  dimin- 
ished milk  yield  first  results,  then  a  period  of  normal  yield  and 


Plants    Affecting   Milk.  137 


finally  an  increase  in  the  quantity,  together  with  an  improvement  in 
quality.  Pastures  or  green  cultivated  forage  containing  many 
buttercups  should  be  avoided,  since  these  plants  are  supposed  to 
produce  red  and  bitter  milk,  especially  before  blooming.  Meadows 
or  pastures  in  which  Euphorbia  plants  are  growing  exert  a  bad 
influence;  they  may  produce  enteritis  with  a  fetid  diarrhea,  also 
paralysis  of  the  bladder  and  hematuria,  and  may  even  cause  abor- 
tion. The  milk  turns  thin  and  bluish. 

Bluish  milk  may  also  result  after  feeding  upon  plants  of  the 
Polygonum  species,  the  ox  tongue  (Anchusa  offic.),  the  cat's  tail 
(Butomus  umbellatus),  the  euphorbia  (Mercurialis),  the  marsh 
marigold  (Ehinanthus  major),  the  forget-me-not  (Myosotis),  and 
after  feeding  upon  poppy-cake  and  green  alfalfa. 

Red  milk  is  produced  by  feeding  blood  root  (Galium  verum), 
madder  (Rubia  tinctorum),  species  of  Karex,  Skirpus,  Equisetum, 
Ranunculus,  Euphorbia  and  after  the  ingestion  of  young  sprouts 
of  both  deciduous  and  coniferous  trees. 

Yellow  milk  results  from  the  elimination  of  plant  coloring 
matter  after  the  feeding  of  carrots,  rhubarb,  yellow  and  red  man- 
gels, and  crocus. 

A  garlicky  taste  may  also  result  from  feeding  large  quantities 
of  poor  straw,  and  according  to  Werenskiold  after  feeding  of  flax 
seed  meal  which  contains  large  quantities  of  weed-seeds,  penny- 
royal (Thlaspi  arvense).  The  taste  of  the  milk  may  also  be 
changed  by  the  ethereal  oils  of  the  following  plants : 

Garlic  (Alium  ursinum),  mint  (Teukrium),  hyssop  (Gratiola 
offic.),  true  camomile  (Matric.  chamomilla),  and  by  rape,  rape- 
cake,  oil  cake,  turnip  tops,  lupins  and  orchids. 

Milk  may  become  fishy  from  feeding  fish  meal  and  through 
pasturing  on  marshy  fields  which  have  been  inundated. 

Milk  turns  bitter  from  feeding  kale,  rutabagas,  turnip  tops, 
lupins,  pea-straw,  lupin  straw,  and  sorrel. 

A  bitter  substance  from  chicory  passes  into  the  milk;  the 
milk  may  coagulate  more  readily  after  the  ingestion  of  thistles  or 
sorrel.  The  ingestion  of  euphorbia,  hellebore,  rushes,  and  hemlock 
twigs  should  be  prevented  on  account  of  the  poisonous  qualities  of 
these  plants.  The  secretion  of  the  active  poisons  of  these  plants 
has,  however,  not  been  proved.  Hop  leaves,  especially  those 
sprayed  with  copper  sulphate,  cause  a  diminution  of  milk  secre- 
tion, or  even  a  cessation  of  the  flow. 

Concerning  the  elimination  of  medicinal  agents  with  the  milk, 
or  the  influence  of  medicinal  agents  on  milk  production  the  follow- 
ing may  be  stated :  The  passage  of  iodine  into  the  milk  after  feed- 
ing potassium  iodide  has  been  proved  by  Peligot  and  Stumpf ;  if 
however  the  iodine  is  fed  in  alkaline  compounds,  or  combined  with 
proteins  and  starches,  even  when  fed  in  large  quantities,  it  does  not 
pass  into  the  milk.  In  the  latter  case  only  the  plasma  of  the  milk 


138  Effect  of  External  Influences. 

contains  the  halogen  in  the  form  of  a  salt,  whereas  in  feeding 
iodized  fats  the  milk  fat  contains  iodine. 

According  to  Rosenhaupt  and  Bucura  the  same  applies  to 
bromine. 

According  to  Stumpf,  Baum  and  Seeliger,  in  feeding  com- 
pounds of  lead  small  quantities  (0.02%)  of  this  substance  pass  into 
the  milk.  The  ingestion  of  such  milk  was  found  harmless  for  ani- 
mals. The  lead  was  eliminated  for  a  longer  period  than  the  time 
during  which  it  was  fed.  Milk  which  contains  salts  of  lead  could 
produce  severe  injurious  effects  if  taken  for  a  long  time  (chronic 
lead  poisoning). 

Feeding  of  salts  of  copper  results  only  in  the  appearance  of 
traces  of  copper  in  the  milk. 

The  feeding  of  iron  preparations  does  not  to  any  noteworthy 
extent  influence  the  contents  of  the  milk. 

Mercury  may  pass  into  the  milk  (Bucura) ;  likewise  arsenic 
when  administered  per  os  or  injected  in  any  form  subcutaneously 
(Bucura,  Ittalie  and  Jesionek). 

Substances  like  aloes,  senna  leaves,  rhubarb  and  croton  may 
influence  the  milk  in  color  and  taste,  and  will  be  partially  eliminated 
with  the  milk. 

According  to  Eost  and  Wiley  boracic  acid  may  pass  into 
human  milk;  likewise  after  the  ingestion  of  Glauber  salts  the 
S03  content  of  the  milk  is  supposed  to  be  increased  (Hess  and 
Schaffer). 

According  to  Baum  tartar  emetic  is  not  found  in  the  milk  of. 
cows  treated  with  this  drug,  whereas  Harms  claims  it  is  eliminated 
with  the  milk. 

The  feeding  of  large  quantities  of  alcohol  effects  a  diminution 
of  the  specific  gravity  and  an  increase  of  the  fat  content  of  the 
milk.  The  quantity  of  the  milk  appears  somewhat  increased  (in 
goats).  Elimination  of  alcohol  with  the  milk  does  not  occur.  Wel- 
ler  and  Teichert  proved  that  alcohol  would  pass  into  the  milk  of 
cows  after  feeding  them  with  large  quantities  of  incompletely  ex- 
tracted distillery  slops. 

Although  Horder  and  Herdegen  claim  the  secretion  of  salicylic 
acid  with  the  milk,  Richter,  Pauli  and  Stumpf  disclaim  its 
elimination  in  large  amounts.  Pauli  and  Stumpf  succeeded  in  de- 
tecting small  quantities  of  salicylic  acid  in  the  milk  of  nursing 
mothers  treated  with  this  substance,  and  also  in  the  urine  of  their 
babies,  as  well  as  in  the  milk  of  experimental  goats.  In  this  regard 
individual  peculiarities  must  also  be  considered  since  in  one  nurs- 
ing mother  the  presence  of  salicylic  acid  was  demonstrated,  where- 
as the  examination  was  negative  in  another  case. 

According  to  Pinzoni  the  same  applies  to  antipyrin.  Salol 
does  not  appear  in  the  milk  after  its  administration. 

Chloroform  and  ether  are  found  in  considerable  quantities  in 
the  milk  after  anesthesia  (Nicloux). 


Drugs  affecting  Milk.  ^39 


Landsberg  failed  to  detect  morphine  in  the  blood,  urine  or  in 
the  organs,  either  after  subcutaneous  or  intravenous  injections, 
and  Stumpf  and  Pinzoni  do  not  believe  that  after  therapeutical 
administration  of  morphine  it  will  pass  into  the  milk  in  demon- 
strable quantities.  This  was  found  by  Ittalie  to  be  the  case  with 
opium. 

Oil  of  turpentine  is  not  eliminated  with  the  milk  (Ittalie), 
and  the  same  is  true  of  santonin  (Coronedi). 

Stumpf  undertook  experiments  with  pilocarpin  without  how- 
ever being  able  to  find  the  pilocarpin  in  the  milk,  although  his 
methods  were  unsatisfactory. 

Atropin  and  fluorescin  administered  subcutaneously,  accord- 
ing to  Fugin  and  Bonanni,  and  Ittalie,  may  be  demonstrated  in 
the  milk. 

It  shcmld  also  be  mentioned  here  that  according  to  Ostertag  meat  of  poisoned 
animals  may  be  eaten  without  harm  to  the  health.  He  established  the  fact  that  meat 
from  animals  which  have  received  medicinal  agents  for  therapeutic  purposes  may  be 
consumed  without  any  possibility  of  danger.  The  harmlessness  of  the  meat  of  poisoned 
animals  has  been  established  by  Frohner  and  Knudsen  for  strychnia,  eserin,  piloearpin 
and  veratrin;  by  Harms  for  nux  vomica  and  tartar  emetic;  by  Feser  for  strychnine  and 
eserin;  by  Spallanzini  and  Zappa  and  Sonnenschein  for  arsenic;  by  Gautier  for  cotton- 
seed cake ;  by  Feser  for  apomorphine ;  by  Peschel  for  colchicum ;  by  Warnke  for  morphine ; 
and  Albrecht  for  litharge. 

Of  course  milk  may  contain  certain  quantities  of  poison  since  the  udder  has  a 
special  function  as  an  excretory  organ.  The  question  of  elimination  of  medicinal  remedies, 
however,  is  not  of  practical  importance  since  the  medicinal  doses  are  relatively  small 
and  their  elimination  occurs  only  in  traces. 

In  this  entire  question  milk  inspection  is  powerless.  Through 
educational  advice  by  the  consulting  veterinarian  the  producers 
may  be  reminded  of  their  duty  corresponding  to  the  prohibitive 
measures,  not  to  include  with  milk  for  the  market  that  produced 
by  animals  which  are  under  treatment  with  certain  drugs.  From 
a  hygienic  standpoint  only  those  remedies  deserve  mention  which 
are  eliminated  for  a  long  period  after  their  administration,  as  for 
instance  lead  and  medicines  whose  prolonged  ingestion  may  pro- 
duce disturbances  of  health  even  in  the  smallest  doses. 

Considering  the  fact  that  in  normal  feeding  with  good  feeds 
of  any  kind  the  individual  influence  is  paramount  in  milk  produc- 
tion, it  becomes  evident  that  in  establishing  regulations  for  pro- 
curing children's  milk  more  stress  should  be  laid  on  the  health  of 
the  animals,  on  good  attendance  and  care  by  healthy  milkers,  and 
on  thorough  cleanliness  of  the  stable,  and  cleanliness  in  procuring 
and  handling  the  milk,  than  on  rigorous  regulations  for  feeding 
which  cannot  be  satisfactorily  carried  out  by  the  owner  on  economic 
grounds,  since  he  must  utilize  the  by-products  or  refuse  of  any 
industry  of  his  vicinity. 

There  is  no  reason  why  pasture  milk,  or  milk  obtained  after 
feeding  green  food  should  be  excluded  from  the  market  as  certified 
or  children's  milk,  especially  if  from  a  dietetical  standpoint  the 
advantages  of  green  feeds  for  cattle  are  considered,  and  the  favora- 


140  Effect  of  External  Influences. 

ble  influence  which  the  pasturing  exerts  on  milk  production  and 
metabolism  be  regarded. 

Spoiled  feed  should  be  prohibited,  and  also  foods  which  are 
readily  subject  to  decomposition  (fresh  residues  of  breweries, 
sugar  refineries,  etc.).  Food  which  is  obtained  through  fermenta- 
tion processes  (hay,  grass,  clover,  mangels,  potatoes,  green  corn, 
stored  in  pits  in  the  ground)  should  if  possible  be  limited,  since 
substances  of  odor  and  taste  are  eliminated  with  the  milk  and 
especially  food  bacteria  which  diminish  the  keeping  qualities  of 
the  milk.  Although  they  might  not  have  a  direct  harmful  influence 
in  the  human  organism  nevertheless  they  may  spoil  the  taste  of  the 
milk. 

The  beneficial  influence  of  pasturage  cannot  alone  be  attributed 
to  the  advantage  of  change  of  feeding,  but  is  also  the  result  of  the 
stimulating  action  of  the  light  and  air  on  metabolism,  and  of  the 
mild  form  of  exercise.  Therefore  in  the  absence  of  pastures  it 
would  be  advisable  to  provide  exercising  paddocks  for  the  animals. 
According  to  Munk  moderate  exercise  increases  the  yield  of  milk 
and  its  proportion  of  solid  substances. 

Excessive  exercise  of  cows  should  be  avoided. 

Although  moderate  exercise  on  rich  pastures  in  connection 
with  other  factors  which  increase  metabolism,  produces  more 
abundant  and  richer  milk,  increased  exercise  reduces  the  quantity 
of  milk  but  increases  its  fat  contents.  In  over-exertion  however 
the  quantity  and  quality  of  the  milk  are  reduced,  and  the  milk  and 
butter  both  develop  an  irritating  taste  (Dolgich). 

Exhausting  transportation  changes  the  milk  production  con- 
siderably, especially  when  during  that  period  the  cows  are  milked 
irregularly,  or  for  advantage  in  selling  the  cows  the  udders  are 
allowed  to  become  engorged  with  milk.  Stasis  mastitis  results, 
which  may  be  cured  only  by  repeated  and  thorough  milkings. 

Excitement  of  any  kind,  such  as  fright,  taking  away  the  calf, 
change  of  surroundings  (new  purchaser),  and  change  of  feed,  may 
for  a  longer  or  shorter  period  cause  a  diminution  of  the  quantity 
of  milk  and  a  change  of  its  quality. 

Backhaus  observed  an  increase  of  over  7%  in  quantity  of 
milk  production  and  8%  of  the  fat  content  after  the  cows  had  been 
curried;  in  other  cases  it  amounted  to  4  and  2y2%,  respectively. 

In  pasturing  cows,  sheds  should  be  provided  for  shelter  from 
the  strong  rays  of  the  sun  and  rain;  otherwise  according  to 
Schwenk  the  yield  becomes  diminished.  Kirsten  observed  a  dimin- 
ution of  the  production  of  milk  after  prolonged  rain.  According  to 
Ingersoll  and  Duncanson,  marked  changes  in  the  weather  may 
even  be  of  significance  during  the  season  when  the  animals  are 
stabled. 

A  rise  or  a  fall  in  the  temperature  may  cause  a  reduc- 
tion in  the  fat  content.  In  the  morning  following  rainy  nights  the 
milk  may  become  richer.  The  influence  of  weather  and  pasture  on 


Method   of  Stablin 


milk  production  has  been  observed  by  various  German  investiga- 
tors, but  the  results  differed  considerably.  Some  observed  a  dimin- 
ution of  the  fat  content,  others  an  increase,  while  some  noted  a 
diminution  of  the  milk  yield,  and  a  number  of  others  detected 
no  reaction  whatsoever.  Following  the  passage  of  a  heavy  thunder 
shower  a  diminution  of  the  milk  yield  and  an  increase  of  the  fat 
content  were  observed  which  corresponded  to  the  increased  activity 
of  the  animal  in  the  equalization  of  the  body  heat. 

If  herds  which  are  pastured  at  night  are  compared  with  those 
which  are  stabled  at  night,  no  favorable  influence  of  the  stabling 
at  night  is  observed,  neither  regarding  the  quantity  of  milk  nor  its 
fat  content.  In  animals  kept  uninterruptedly  out  of  doors  the  fat 
content  increased  more  rapidly  than  in  those  kept  in  stables.  In  the 
former  the  live  weight  increased  more  rapidly  than  in  the  latter ; 
in  other  experiments,  however,  the  results  remained  the  same. 
Wychgram  in  his  experiments  in  East  Friesland  found  the  milk 
yield  in  stabled  animals  increased,  but  the  fat  content  diminished 
as  compared  to  milk  from  cows  at  pasture. 

The  cows  which  furnish  the  milk  supply  of  cities  as  a  rule  are 
kept  in  large  stables.  The  stabling  of  course  should  be  such  that 
the  health  of  the  animals  does  not  suffer,  and  means  should  be 
provided  for  a  pure  milk  production. 

It  is  not  so  difficult  to  comply  with  these  two  requirements  as 
some  farmers  believe.  They  may  be  attained  without  great  ad- 
ditional cost,  since  the  increase  of  expense  for  proper  stabling  is 
amply  covered  by  the  increased  income  from  the  animals. 

In  equipping  so-called  model  stables,  an  extraordinary  amount 
is  usually  expended  for  luxury  in  the  equipment  and  furnishings, 
so  that  the  practical  farmer  on  visiting  such  stables  is  frequently 
disheartened,  instead  of  being  encouraged  to  change  his  more 
primitive  place  of  milk  production  to  comply  with  these  models, 
since  a  simple  calculation  of  the  expense  of  such  buildings  for  keep- 
ing cows  shows  him  that  a  change  of  his  stable  conditions  to  equal 
those  of  the  models  is  impossible. 

A  really  valuable  modern  stable  however  may  be  built  at  the 
present  time  without  considerable  additional  cost,  and  may  be 
equipped  so  that  the  additional  expense  of  milk  production  due  to 
the  wearing  out  of  the  building  is  not  greater  than  the  cost  of 
repairing  an  unsanitary  stable. 

For  the  erection  of  a  new  stable  a  dry  building  site  should  be 
chosen  if  possible,  or  at  least  the  penetration  of  dampness  from  the 
ground  should  be  prevented  through  separation  and  isolation  of 
the  ground  and  walls.  Only  under  such  conditions  can  the  require- 
ment of  clean  walls  be  attained. 

The  floor  of  the  stable  must  be  water  tight  and  without  cracks 
and  holes,  and  should  permit  of  ready  cleansing  and  disinfection. 
It  is  to  be  regretted  that  such  water  tight  floors  are  frequently  too 
cold  for  milk  cows,  and  the  action  of  the  cold  must  be  diminished 


142  Effect  of  External  Influences. 

by  the  provision  of  wooden  planks.  The  floor  surface  must  be 
rough  enough  to  afford  the  animals  a  solid  footing. 

The  walls  of  the  stable  should  be  provided  to  a  height  of  6  feet 
with  an  unpenetrable,  washable  covering,  which  however  should 
not  be  dark  as  was  customary  in  the  past,  in  order  to  hide  the  ac- 
cumulated dirt,  but  should  be  light  in  order  that  dirt  may  be  readily 
seen  and  removed. 

The  stable  ceiling  should  be  separated  from  the  feed  loft 
situated  above  it,  by  an  air  space,  and  should  be  whitewashed,  the 
same  as  the  walls.  In  order  that  it  should  be  impervious  to  the  sta- 
ble odors,  the  ceiling  on  the  inside  of  the  stable  should  be  covered 
with  minerally  treated  pasteboard.  The  air  space  between  the 
ceiling  and  feed  loft  should  communicate  with  the  outside  air. 

Angles  and  corners  should  be  rounded  off,  in  order  to  prevent 
the  accumulation  of  dust. 

In  large  herds  the  erection  of  several  small  separated  stables 
should  be  given  preference  to  a  large  single  stable  for  all  animals. 
Each  of  the  stables  should  be  made  for  16  to  20  animals.  The 
advantages  of  the  smaller  buildings  are  manifested  in  better  pos- 
sibilities of  ventilation,  the  easier  removal  of  manure,  cheaper  con- 
struction of  the  roofs,  less  excitement  for  the  animals,  and  better 
possibility  of  caring  for  and  feeding  the  individuals.  Against  these 
advantages  the  absence  of  close  supervision,  which  is  afforded  by 
the  large  stable,  is  not  material  (Schuppli). 

The  animals  should  be  placed  in  rows  in  such  a  way  that  the 
light  may  strike  them  from  the  side  or  from  the  rear. 

In  order  to  provide  a  great  amount  of  light,  high,  broad  win- 
dows and  transparent  instead  of  only  translucent  window  glass 
should  be  installed,  the  total  lighting  surface  of  which  should 
amount  to  at  least  one-twentieth  of  the  floor  space  of  the  stable 
(according  to  Schlossmann  the  comparison  should  not  be  much  less 
than  one-fifth). 

Placing  the  animals  face  to  face  should  be  avoided  on  account 
of  the  danger  of  infection  with  tuberculosis,  or  this  danger  should 
at  least  be  diminished  by  broadening  the  passages. 

The  windows  should  commence  from  5  to  6  feet  from  the  floor. 
Artificial  illumination  should  be  provided  for;  transoms  assist  in 
the  airing  of  the  stable  by  allowing  ingress  of  natural  atmosphere. 

The  ventilation  should  be  calculated  so  that  the  air  of  the  sta- 
ble should  not  contain  more  than  3:1000  (Marker),  or  1:1000 
(Schlossmann)  carbonic  acid.  According  to  Schlossmann  a  cow 
weighing  1,100  Ibs.  produces  12.71  cubic  feet  of  carbonic  acid, 
which  would  have  to  be  diluted  by  1,000  times  its  quantity  of  in- 
troduced air  in  order  to  contain  only  1 :1000  of  the  required  quan- 
tity in  the  air.  This  introduction  of  air  is  made  possible  by  three 
changes  of  air  per  hour,  without  permitting  a  disturbing  draught. 
Therefore,  according  to  Schlossmann,  the  air  space  in  a  stable  for 
cows  weighing  1,100  Ibs.  must  be  12,710 :72=176.5  cubic  feet.  Gen- 


Stable  Construction. 


erally  however,  on  account  of  economic  grounds  a  much  smaller 
air  space  has  to  answer  the  purpose.  Schuppli  even  believes  that 
a  reduction  of  air  space  below  the  ordinary  70  to  88  cubic  feet  of 
air  per  animal  would  be  permissible  when  the  ventilation  system 
is  working  properly,  and  is  satisfied  with  42  cubic  feet  per  animal 
when  the  ventilation  provides  for  sufficient  renewal  of  air. 

The  supply  of  air  is  provided  by  wide  shafts  which  take  the 
air  from  the  outside  at  a  height  of  three  feet,  lead  it  up  through 
the  wall  and  expel  it  from  the  stable  ceiling  into  the  stable.  The 
foul  air  escapes  through  an  opening  close  to  the  stable  floor  of  one 
or  more  discharge  shafts,  which  are  carried  to  the  highest  point  of 
the  stable  ceiling,  or  sideways  from  the  median  line  upwards  and 
outwards.  The  total  capacity  of  the  discharge  shafts  should  be 
somewhat  smaller  than  the  capacity  of  the  supply  shafts. 

In  intensive  ventilation,  especially  when  the  air  space  provided 
for  each  cow  is  considerable,  heating  of  the  stable  might  become 
necessary,  a  provision  which  of  course  could  not  be  considered  for 
the  ordinary,  medium-sized  or  even  larger  establishments. 

Well-installed  transom  ventilators,  if  sufficient  attention  is 
given  to  their  operation,  would  supply  the  desired  change  of  air 
even  without  heating,  and  at  the  same  time  maintain  the  desired 
temperature  of  16°  to  18°  C.  If  heating  is  provided  the  air  sup- 
ply shafts  should  open  over  the  heaters. 

In  providing  stalls,  from  the  standpoint  of  cleanliness  only 
the  so-called  Holland  type  of  stable  floor  should  be  recommended 
for  dairy  stables.  The  principle  on  which  these  are  built  consists 
of  rather  short  standing  space  with  broad,  deep  drainage  trough 
in  the  rear.  The  urine  and  manure  falls  into  this  trough,  and 
soiling  of  the  animal  is  thereby  prevented  while  the  contamination 
of  the  bedding  is  minimal. 

Among  objections  to  the  Holland  type  of  stables,  it  is  sometimes  claimed  that  the 
animals  cannot  move  sufficiently  and  that  such  stabling  constitutes  a  cruelty  to  the 
animals,  etc.  The  best  proofs  against  these  objections  without  doubt,  are  the  facts  that 
in  countries  which  are  in  the  highest  state  of  agricultural  development  this  method  of 
stabling  has  been  practiced  for  a  long  time,  and  the  animals  soon  get  used  to  this  method 
of  stabling  without  suffering  in  their  general  condition  or  being  affected  in  their  milk 
production. 

In  the  Holland  method  the  tails  of  the  animals  are  tied  with  a 
cord  in  such  a  way  that  while  the  animal  stands  its  tail  hangs  in 
a  natural  position,  but  when  lying  down  the  tail  is  kept  elevated 
so  that  it  cannot  be  submerged  in  the  contents  of  the  drain. 

The  cords  are  tied  to  a  rod  which  runs  near  the  ceiling,  parallel 
with  the  row  of  cows,  or  the  cords,  with  weights  attached,  are 
allowed  to  hang  over  this  rod. 

The  shortness  of  the  stalls  of  course  requires  a  low  feeding 
trough,  over  which  the  animals  may  extend  their  heads  while  lying 
down.  In  order  that  the  animals  may  not  annoy  each  other,  the 
individuals  are  separated  by  means  of  partitions,  which  extend 


144  Effect  of  External  Influences. 

upwards  to  the  height  of  the  head  or  the  shoulder  and  at  the  same 
time  have  fastenings  which  are  used  for  tying  the  cows. 

To  prevent  the  cows  from  backing  into  the  drain,  a  moulding 
of  one-half  inch  is  provided  along  the  upper  border  of  the  drain 
trough.  This  moulding  holds  the  slipping  foot  and  makes  possible 
the  placing  on  the  floor  of  wooden  slats  when  pregnant  -animals  are 
about  to  calve.  The  fundamental  principle  against  the  possibility 
of  slipping  is  the  above-mentioned  provision  of  a  sufficiently  rough 
stable  floor. 

The  width  of  the  stalls  should  be  about  S1/^  feet,  the  length  51/4 
to  53/4  feet. 

The  most  satisfactory  feeding  troughs  are  those  which  cor- 
respond to  the  conditions  of  natural  feeding  in  the  pasture,  and 
they  should  be  so  constructed  that  they  will  serve  for  animals  of 
all  ages  with  the  possibility  of  providing  partitions  in  order  to 
separate  the  individual  rations.  For  watering  the  animals  it  is 
advisable  to  provide  each  stall  with  automatic  water  supply. 

•The  accumulated  litter  in  the  drain  trough  should  be  mechan- 
ically removed  as  often  as  possible  into  liquid  manure  pits  which 
terminate  in  a  tunnel  with  collecting  canals,  or  the  litter  may  be 
thrown  into  a  chute  through  a  shaft  leading  to  a  water-tight  liquid 
manure  pit  the  size  of  which  should  be  so  arranged  that  88  to  106 
cubic  feet  of  manure  space  are  allowed  for  each  animal. 

Over  the  liquid  manure  pit  on  wooden  lattice  frames,  or  along- 
side of  it,  should  be  placed  the  manure  pile,  with  30  square  feet  of 
surface  for  each  grown  animal.  On  account  of  the  desired  decom- 
position of  the  material  the  first-mentioned  arrangement  of  the 
manure  over  the  liquid  manure  pit  is  most  desirable.  There  should 
be  a  separation  between  the  stable  and  the  manure  pile  of  at  least 
20  feet  and  the  latter  should  be  placed  on  the  side  opposite  to  the 
principal  direction  of  the  wind  in  that  locality.  The  outlets  of 
the  manure  drains  should  be  closed  from  the  stable  by  trap  or  slid- 
ing doors. 

Good  straw  should  be  selected  for  the  bedding  of  animals. 
The  question  of  straw  which  is  very  important  in  localities  where 
but  little  is  grown  is  favorably  solved  by  the  Holland  method  of 
stabling,  since  by  this  method  a  great  deal  of  straw  is  saved  by 
the  short  stalls  with  but  slight  soiling  of  the  animals.  Forest  and 
shade  leaves  are  not  recommended,  since  it  is  claimed  that  milk 
troubles  result  from  their  use.  Turf  straw,  shavings  and  saw- 
dust should  be  avoided  if  possible  on  account  of  the  formation  of 
dust,  but  should  not  be  excluded  if  good  straw  bedding  cannot  be 
obtained.  The  use  of  bed  straw  should  be  prohibited  in  milk 
stables.  The  feeding  of  the  cattle  must  be  performed  after  milking, 
on  account  of  raising  the  dust.  The  removal  of  the  manure  and 
the  cleaning  of  the  animals  should  take  place  at  least  one  hour  be- 
fore the  milking. 

Complaint  is  frequently  made  to  hygienists  that  the  require- 


Complete  Milking. 


ments  which  are  made  by  them  relative  to  stable  hygiene  must  in- 
crease the  cost  of  keeping  the  animals,  and  thereby  increase  the 
cost  of  the  milk.  This  view  is  only  justified  to  a  slight  extent. 
Stable  hygiene  if  satisfactorily  adjusted  will  result  in  a  considera- 
ble increase  in  the  yield  of  the  dairy  animals. 

The  economic  losses  which  are  induced  by  udder  affections, 
which  spread  with  especial  rapidity  in  filthy  stables  and  from 
unclean  milking,  have  been  discussed  in  a  special  chapter.  Atten- 
tion should  only  be  directed  here  to  the  increased  production  fol- 
lowing proper  attention  to  cleanliness  of  the  animals,  and  to  the 
findings  of  Bloymeyer  and  others,  according  to  which  cows  in  well 
ventilated  stables,  all  other  things  being  equal,  yielded  from  450 
to  480  liters  more  milk  per  head  each  year  than  cows  kept  in  unven- 
tilated  stables. 

The  favorable  influence  of  exercise  and  light  work  has  also 
been  discussed  above.  If  possible  the  animals  should  be  given  an 
opportunity  to  run  out  of  doors  in  a  paddock  for  at  least  one  to  two 
hours  daily,  even  in  the  winter  months. 

Of  all  outside  influences,  regular  and  complete  milking  con- 
stitutes the  most  prominent  stimulant  for  inducing  the  activity  of 
the  udder.  It  is  known  that  cows  which  are  milked  three  or  four 
times  in  each  twenty-four  hours  give  more  milk  than  those  which 
are  milked  only  twice  (Backhaus).  The  increased  yield  from  milk- 
ing three  times  amounts  to  from  10  to  15%  more  than  the  pro- 
duction obtained  from  two  milkings ;  in  four  milkings  the  increase 
amounts  to  from  6  to  8%  as  compared  with  three  milkings. 

The  quantity  and  composition  of  the  milk  at  each  milking  de- 
pend somewhat  upon  the  time  which  has  elapsed  since  the  last  milk- 
ing. According  to  general  experience  the  morning  milk  is  of 
greater  quantity  with  a  smaller  amount  of  fat,  in  comparison  with 
quantity  and  fat  content  of  the  evening  milk.  During  the  night 
absolute  rest  prevails,  whereas  during  the  day  the  influence  of  light 
and  motion  causes  an  increase  of  metabolism  which  is  also  mani- 
fested in  the  variations  of  the  body  temperature  shown  by  the 
animal  in  the  morning  and  evening. 

The  differences  in  milk,  which  are  obvious  in  irregular  or 
so-called  broken  milkings,  may  be  explained  in  a  different  way ;  that 
is  while  the  milk  at  the  beginning  of  the  milking  contains  0.5  to 
1.5%  fat,  in  the  middle  of  the  milking  it  shows  2  to  3  to  4%,  and 
again  rises  towards  the  end,  during  the  last  strokes  of  milking  to 
8  and  10%  (Melander,  Kaull,  Gotta,  de  Vrieze).  The  fat-free  solid 
substances  are  subject  to  slight  changes  (according  to  Boussin- 
gault  the  fluctuation  amounts  to  from  0.2  to  0.28%).  The  condi- 
tions in  the  milk  when  the  calf  sucks  are  similar. 

A  truly  plausible  explanation  can  hardly  be  given  to  the  supposition  of  a  separation 
of  cream  in  the  udder  (Zschokke)  ;  likewise  it  hardly  seems  reasonable  to  suppose  that 
the  thin  plasma  particles  flow  towards  the  cistern,  while  the  fat  globules  as  a  result  of 
greater  fusion  and  friction  are  retained,  and  are  only  pressed  towards  the  larger  milk 
ducts  and  the  cistern  by  the  newly  formed  milk  which  is  secreted  during  the  act  of 
10 


146  Effect  of  External  Influences. 

milking.  The  principal  cause  lies  probably  in  the  fact  that  the  separation  of  the  fat 
represents  a  greater  expenditure  of  energy  than  the  secretion  of  the  plasma.  If  the  cell 
is  exhausted  by  previous  milking  it  then  secretes  milk  during  the  period  of  rest  which 
is  especially  rich  in  plasma  and  poor  in  fat.  Through  this  period  the  alveoli  and  milk 
ducts  are  dilated,  and  the  gland  cell  becomes  flat  and  is  at  rest.  In  this  position  of 
rest  it  recovers  and  is  ready  for  renewed  action  when,  through  renewed  milking 
operations,  the  fluid  is  withdrawn  and  stimulation  of  the  secretion  is  applied  through 
the  teat. 

If  the  milk  is  removed  without  this  stimulation  of  secretion,  with  the  aid  of  a 
milking  tube,  only  milk  poor  in  fat  flows  from  the  cistern  and  the  larger  milk  ducts,  and 
the  flow  ceases  as  soon  as  pressure  is  no  longer  exerted  on  the  secretion. 

If,  however,  through  milking  (or  other  stimulation)  new  secretion  takes  place,  the 
rested  gland  cell  engorges  with  nutritive  material,  and  converts  it  into  fat,  which  is 
separated  during  the  milking  in  increased  quantities  until  the  secretion  of  plasma  and 
the  separation  of  fat  cease,  which  marks  the  height  of  these  two  processes  in  the 
secretion  of  milk.  Through  an  increased  stimulation  by  additional  milkings  the  cell 
may  be  further  stimulated  to  a  special  production,  which  consists  in  an  increased  fat 
formation  (Hegelund).  Henkel  succeeded  by  this  procedure,  in  increasing  the  quantity 
of  milk  by  2.4%,  and  the  fat  content  by  6.2%. 

As  already  mentioned  Hegelund 's  method  requires  additional 
work,  which  may  possibly  lead  to  the  hiring  of  additional  help 
and  must  be  considered  (Kirchner),  when  estimating  profit  and 
expense.  The  principal  factor  in  the  various  methods  of  milking 
lies  in  the  thorough  milking  out  of  the  udder,  which  will  retain 
its  maximum  of  production  only  by  such  practice.  Henkel  suc- 
ceeded in  demonstrating  the  extent  to  which  the  milk  production  de- 
pends on  the  thoroughness  of  the  milker.  The  production  of  a  cow 
when  milked  by  a  thorough  milker  amounted  to  8.1  kg.  (17.8  Ibs.) 
of  milk,  with  4.2%  of  fat;  by  a  less  satisfactory  employee  to  only 
5.6  kg.  (12.31bs)  with  2.7%  of  fat. 

At  the  same  time  it  is  immaterial  what  method  of  milking  is 
pursued,  that  is,  whether  the  teats  are  milked  crosswise,  or  those 
on  one  side,  or  those  of  opposite  quarters,  simultaneously.  Milk- 
ing of  a  single  teat  at  a  time,  which  of  course  is  not  customary, 
yields  less  milk,  and  the  last  milked  quarter  is  the  poorest  in  fat 
(Lepoutre  and  Babcock).  The  influence  of  special  methods  of  milk- 
ing has  been  more  fully  discussed  in  the  chapter  on  the  procuring 
of  milk.  According  to  Klinkmiiller  the  milk  yield  of  the  right  half 
of  the  udder  is  3. 97  kg.  (8.7  Ibs.),  the  left  3.65  kg.  (8.03  Ibs.),  with 
fat  contents  of  3.65  and  3.31%  respectively.  The  cause  of  this 
increased  production  of  the  right  half  of  the  udder  is,  according 
to  Klinkmiiller,  the  result  of  the  practice  of  milking  the  right  half 
first,  and  therefore  it  is  advisable  to  practice  alternation  in  milking, 
from  right  and  left. 

If  milking  stools  are  used  care  should  be  taken  that  the 
milkers  do  not  take  hold  of  the  seat  with  their  hands.  The  most 
recommendable  stools  have  only  a  single  foot,  and  are  secured 
around  the  body  by  a  strap.  Switching~of  the  animal's  tail  must 
be  prevented  during  milking  by  tying  it  up,  or  by  other  effective 
contrivances. 

Conditions  which  prevail  in  the  handling  of  milk  after  it  has 
been  procured  are  of  special  importance  in  providing  milk  of  Hie 
best  quality.  The  changes  which  milk  undergoes  have  been  dis- 


Milk  Pails. 


cussed  sufficiently  for  the  purpose  of  milk  hygiene  in  special  chap- 
ters. Those  points  principally  should  be  emphasized  which  are  to 
be  followed  during  the  drawing  and  preparation  of  the  milk,  in 
order  to  check  or  prevent  undesirable  and  early  decomposition 
of  the  product. 

This  relates  primarily  to  cleanliness.  The  requirements  of 
milk  hygiene  go  hand  in  hand  in  this  respect  with  the  purely 
economic  requirements  of  the  dairy  industry. 

If  it  is  considered  how  much  milk  spoils  prematurely  on  ac- 
count of  improper  care  and  the  amount  of  loss  which  is  sustained 
when  the  creameries  have  to  discard  hundreds  of  pounds  of  cheese 
on  account  of  improper  handling  of  milk,  then  the  economic  value 
of  cleanliness  in  the  stable  becomes  obvious.  The  Holland  method 
of  stabling,  cleaning  of  the  cows  and  especially  the  udders  are 
quite  simple  but  important  factors  in  such  cleanliness. 

In  keeping  the  udder  clean  special  attention  should  be  given 
towards  preventing  its  contact  with  filth. 

Dry  cleaning  with  suitable  straw,  or  rough  towel  is  prefera- 
ble to  moist  washing  which  often  consists  in  spreading  the  softened 
dirt  over  the  entire  udder.  If  the  dry  method  of  cleaning  the  ud- 
der is  used  such  milking  pails  should  be  provided  which  will  pre- 
vent the  milk  from  becoming  contaminated  by  the  dust  originating 
from  the  cleaned  udder. 

If  the  udders  are  washed  it  should  be  done  with  lukewarm 
water  without  soap.  Subsequently  the  udders  should  be  rubbed  dry 
and  slightly  lubricated  with  paraffin  salve.  Even  with  these  simple 
operations  milk  may  be  obtained  containing  only  very  small  num- 
bers of  bacteria,  and  would  suffice  for  all  practical  purposes.  Cov- 
ering the  animals  with  linen  sheets,  disinfection  of  the  udder  in 
water-tight  bags,  and  washing  of  the  entire  animal  represent  some- 
what exaggerated  procedures,  and  besides  they  require  additional 
expense,  which  can  be  afforded  only  through  a  special  increase  of 
the  price  of  milk. 

The  milk  pails  should  be  so  constructed  that  they  will  pre- 
vent dust  and  dirt  from  falling  into  the  milk.  This  is  accomplished 
by  using  covered  pails,  which  possess  a  special  receiving  tube  sup- 
plied with  a  funnel  for  taking  in  the  milk.  Between  the  receiving 
tube  and  the  funnel  an  arrangement  for  filtering  through  cotton 
may  be  placed.  The  so-called  Algauer  milk  pails  are  provided 
with  such  arrangements ;  likewise  the  Konigsf  order  milk  pails  and 
the  sanitary  pails  of  Gurler  and  North.  The  funnel  should  be 
rinsed  and  provided  with  a  fresh  piece  of  cotton  after  the  milking 
of  each  cow. 

After  milking  is  finished  the  milk  should  be  immediately  taken 
from  the  stable.  This  is  frequently  accomplished  by  pouring  it 
into  a  funnel  arrangement  fastened  to  the  wall  through  which 
the  milk  passes  into  a  suitable  tin  lined  tube  to  the  milk  room. 
This  tube  should  be  removable  in  order  that  it  may  be  properly 


}48  Effect  of  External  Influences. 

cleaned.  In  the  milk  room  the  milk  is  further  treated  by  another 
straining  and  cooled  by  simultaneous  aeration  after  which  it  is 
either  directly  filled  into  bottles,  cans  or  collected  in  a  vat  in  order 
that  it  may  be  thoroughly  mixed. 

The  milk  should  be  handled  as  little  as  possible,  since  each 
manipulation  not  absolutely  necessary,  means  a  poorer  condition 
of  the  product  from  a  hygienic  standpoint.  The  producer  there- 
fore after  straining  the  milk  through  cotton  strainers  should  cool 
it  and  fill  it  into  clean  bottles  or  well-galvanized  and  properly 
cleaned  cans. 

The  straining  of  milk  through  straining  cloths  which  have 
been  carelessly  cleansed  by  rinsing  in  cold  water,  and  which  in 
most  instances  fail  to  answer  the  purpose  on  account  of  their  large 
meshes,  is,  it  is  to  be  regretted,  in  most  instances  merely  a  pre- 
tense, which  only  tends  to  further  spoil  the  dirty  milk.  Milk  which 
is  obtained  in  an  unclean  way  cannot  be  deprived  of  its  poor 
qualities  by  any  mechanical  means,  since  the  filth  dissolves  and  the 
bacteria  pass  through  the  straining  cloths  and  the  cotton  filter.  If 
the  accidentally  contaminating  bacteria  are  removed  immediately 
during  the  milking  (cotton  filter  in  the  funnel  of  milk  pail),  a  con- 
siderable improvement  of  the  milk  results.  The  value  of  artificial 
cleaning,  however,  will  continue  to  decrease  in  proportion  to  the 
length  of  time  elapsing  between  the  time  of  milking  and  cleaning. 
If  the  cleaning  of  dirty  milk  is  accomplished  only  hours  afterwards 
at  the  collecting  places  and  creameries  it  should  be  considered  as 
direct  fraud,  which  gives  the  product  the  appearance  of  good  qual- 
ity without  however  improving  it  in  any  way.  In  such  cases  filtra- 
tion and  centrifugalization  only  serve  as  means  of  deception. 
Filthy  milk  which  has  been  subsequently  cleaned,  must  in  spite  of 
its  cleaned  condition  be  considered  as  spoiled  in  the  sense  of  the 
pure  food  law,  even  if  no  changes  are  yet  apparent  in  it. 

In  milk  control  work  there  are  frequent  opportunities  for 
confiscating  dirty  market  milk,  and  not  infrequently  the  examina- 
tion reveals  that  the  contamination  of  the  milk  consists  in  dust- 
sized  particles  and  cow  manure,  all  of  the  same  caliber,  which  in- 
dicates that  the  milk  has  been  subjected  after  milking,  to  a  straining 
process  which  permitted  the  manure  particles  which  had  been  dis- 
integrated during  the  process  of  milking  to  pass  through  the 
strainer.  Unstrained  milk  obtained  under  filthy  conditions  usual- 
ly shows  the  presence  of  course  straw  particles,  manure,  bits  of  fod- 
der and  cow  hair. 

After  straining,  the  milk  is  allowed  to  flow  down  over  the  out- 
side of  a  double  corrugated  surface,  or  a  series  of  parallel  horizon- 
tal pipes  for  the  purpose  of  cooling  and  simultaneous  aeration; 
these  surfaces  are  kept  cool  through  pipes  containing  running 
water,  ice  water  or  brine.  Especially  practicable  and  serviceable 
are  the  so-called  round  coolers  which  are  provided  with  spiral 
pipes,  covered  with  tinned-copper  sheets,  over  which  the  milk  runs 
in  a  thin  layer. 


Aeration. 


It  will  be  proper  to  describe  here  very  briefly  the  changes 
which  milk  undergoes  through  freezing.  The  freezing  of  milk  oc- 
curs with  remarkable  frequency  in  the  winter  time,  when  the  milk  is 
subject  to  long  transportation.  There  is  no  change  in  the  number 
of  bacteria  which  were  present  at  the  moment  of  freezing  until 
after  the  thawing  of  the  milk.  There  is  neither  diminution  nor 
marked  increase. 

According  to  the  data  of  Vieth,  Kaiser  and  Schmieder,  Hen- 
zold,  Bordas  and  Raczkowski,  Fritzmann  and  Mai  it  may  be  seen 
that  in  the  freezing  of  milk  a  marked  separation  takes  place.  Mai 
found  that  such  milk  under  certain  conditions  may  appear  at  the 
first  glance  like  ordinary  milk,  although  it  is  really  frozen.  Crystal 
needles  of  ice  make  their  appearance  in  such  milk.  If  the  freezing 
continues  layers  of  ice  appear  at  the  sides  of  the  milk  cans  and  on 
the  surface,  thus  enclosing  a  central  fluid  portion.  The  upper 
part  of  the  milk  containing  the  cream  layer  freezes  more  loosely, 
in  a  spongy  leaf-like  manner.  After  thawing,  the  milk  has  its 
original  consistence  and  its  original  odor  and  taste.  The  peroxi- 
dase  content  also  remains  unchanged. 

The  milk  inspector  must  consider  the  separation  of  milk 
during  freezing.  In  taking  a  sample,  special  care  should  be  taken 
to  determine  whether  the  milk  cans  or  other  vessels  already 
contain  ice.  Frozen  milk  should  not  be  sold  to  customers  until 
thoroughly  thawed. 

The  aeration  of  milk  permits  the  escape  of  carbonic  acid, 
hydrogen  and  sulphide  of  hydrogen,  and  supplies  the  milk  with 
air,  so  that  in  all  probability  the  development  of  certain  bacteria 
is  checked,  which  otherwise,  if  the  milk  had  been  filled  into  con- 
tainers in  a  warm  and  un-aerated  condition,  would  have  imparted 
to  the  milk  a  sharp,  disagreeable  animal  taste  and  odor  ;  the  milk 
would  have  been  "suffocated." 

The  corrugated  surface  coolers  are  especially  suitable  for 
use  in  small  dairies. 

The  cans  into  which  the  milk  is  filled  after  cooling  should  be 
tinned  in  a  satisfactory  manner.  It  is  to  be  regretted,  however, 
that  this  is  the  case  only  with  new  cans.  The  tin  covering  espe- 
cially on  the  places  where  the  outside  strengthening  bands  are 
placed,  is  very  imperfect,  and  after  a  shorter  or  longer  time 
defects  in  the  lining  develop,  which  soon  result  in  an  extensive 
formation  of  rust.  The  oxidation  of  the  iron  finally  results  in 
tears  and  holes  which  produce  deep,  sharply  circumscribed  depres- 
sions in  the  side  of  the  can  in  which  rust,  decomposed  milk  and 
slime  accumulates. 

The  transportation  of  milk  in  rusty  cans,  or  those  in  which 
the  lining  has  become  damaged,  gives  it  a  disagreeable  tallowy 
taste. 

Milk  should  be  protected  from  bright  light.  Sun  rays  and 
indirect  daylight  may  give  the  milk  a  tallowy  rancid  odor  and 


Effect  of  External  Influences. 


taste,  in  the  same  manner  as  is  the  case  with  the  prolonged  action 
of  ultra-violet  rays. 

It  is  important  during  transportation  that  the  vessels  be 
closed  in  an  air  tight  manner,  and  with  a  cover  consisting  of 
non-porous  material. 

All  milk  utensils  should  be  cleaned  with  hot  soda  solution, 
with  subsequent  rinsing  in  fresh  pure  water,  and  if  possible  com- 
bined with  steam  sterilization  and  rapid  drying  in  places  protected 
from  dust. 

The  transportation  of  milk  should  be  rapid,  and  where  pos- 
sible it  should  be  shipped  after  each  milking. 

In  creameries  the  treatment  of  milk  after  its  receipt  should 
be  principally  confined  to  cooling.  This  cooling  is  carried  out  in 
deep  cooling  appliances  or  double  coolers  in  which  the  abstraction 
of  the  heat  takes  place  through  water  at  the  point  at  which  the 
milk  flows  into  the  cooler,  and  the  lower  part  is  further  cooled 
with  ice  water  or  with  brine.  All  further  manipulation  and  at- 
tempted improvements  of  milk  for  drinking  purposes  are  of  no 
use.  Spoiled  milk  should  be  excluded  from  the  market  and  not  be 
subjected  to  renovating  processes. 

Thus  in  some  creameries  it  is  customary  to  clean  the  milk  not 
only  by  renewed  filtration,  but  also  by  centrifugalization,  which  is 
frequently  done  on  the  supposition  that  the  bacterial  content  of 
milk  becomes  reduced  through  such  treatment.  This,  however,  is 
impossible  ;  on  the  contrary,  such  milk  often  becomes  contaminated 
again  by  bacteria  from  the  non-sterilized  centrifuges,  and  even  if 
the  milk  is  centrifuged  in  a  sterilized  apparatus  only  those  bacteria 
will  be  eliminated  which  adhere  to  the  courser  bodies  having  a 
higher  specific  gravity  (pus,  fibrin,  filth,  casein  coagulum,  etc.). 

The  separator  slime  therefore  contains  principally  fodder  and 
manure  bacteria,  lactic  acid  bacteria,  species  of  milk  moulds,  and 
bacteria  of  those  fermentation  processes  which  take  place  in  the 
residue  of  milk  cans  and  transportation  vessels,  and  further  the 
specific  causative  agent  of  mastitis  occurring  in  pus. 

Therefore,  although  a  great  number  of  bacteria  are  removed, 
the  bacterial  count  through  plating  of  the  centrifuged  milk  dis- 
closes a  considerably  larger  number  of  bacterial  colonies  than 
was  the  case  in  the  milk  prior  to  centrifulgalization,  although  the 
short  time  of  the  centrifuging  process  does  not  permit  of  an 
actual  increase  of  the  bacteria.  Severin  observed  an  apparent 
increase  in  bacteria  up  to  70%.  This  may  be  explained  by  the 
fact  that  through  centrifugalization,  bacterial  clumps  and  colonies 
floating  in  the  milk,  and  the  clumps  of  pus  and  fatty  leucocytes 
which  have  embodied  bacteria,  are  broken  apart,  and  the  bacteria 
are  thereby  distributed  in  the  milk.  Therefore,  in  spite  of  the 
removal  of  considerable  numbers,  there  is  an  apparent  increase. 
This  distribution  is  such  that  the  separator  slime  and  cream 
are  considerably  richer  in  bacteria  than  the  skim  milk.  The 


Bacteria  in  Cream. 


richness  of  the  cream  in  bacteria  may  on  one  hand  be  explained 
by  the  fact  that  large  quantities  of  bacteria  are  dragged  upward 
with  the  fat  globules,  and  on  the  other  hand  by  the  fact  that 
leucocytes  containing  bacteria,  inflammatory  products,  etc.,  which 
possess  a  lower  specific  gravity,  through  fatty  changes  or  fat 
enclosures,  are  taken  up  with  the  fat  globules  into  the  cream. 

The  most  important  factor  in  the  spoiling  of  milk  in  cream- 
eries may  usually  be  found  in  its  being  kept  for  too  long  a  period 
before  it  is  marketed. 


CHAPTER  VIII. 

BACTERIA  IN  MARKET  MILK;   THEIR   ORIGIN  AND 

ACTION. 

Before  milking  is  commenced  the  udder  should  be  cleansed 
of  all  adhering  dirt.  Cleanliness  in  milking  is  one  of  the  most 
important  factors  in  giving  the  milk  good  keeping  qualities.  Sub- 
sequent cleansing  through  straining,  nitration,  centrifugaliza- 
tion,  etc.,  is  of  little  purpose  after  the  dirt  particles  (straw, 
manure,  dirt)  have  once  imparted  to  the  milk  their  soluble  con- 
stituents, and  an  actual  inoculation  has  been  accomplished  with 
the  bacteria  of  filth. 

The  tail  of  the  cow  should  be  tied,  in  order  to  prevent  bacteria  from  the  skin 
being  thrown  into  the  milk  by  its  switching.  If  left  free  it  may  even  subject  the  milk 
to  contamination  with  coarser  substances. 

The  importance  of  the  effect  on  human  health  of  bacteria 
which  fall  into  the  milk,  and  which  multiply  therein  when  milk 
is  improperly  procured,  is  not  known,  but  the  thought  is  at  least 
repulsive  when  it  is  considered  that  milk  consists  of  a  manure  sus- 
pension of  a  bacterial  culture,  and  on  this  ground  alone  absolute 
cleanliness  in  milking  should  be  insisted  upon.  In  order  to  attain 
this  it  is  again  necessary  to  provide  a  properly  ventilated  and 
well  kept  stable,  as  well  as  milk  room.  The  veterinarians  can 
in  no  way  obtain  a  better  recognition  of  the  milk  problem  than 
by  always  pointing  out  to  the  farmer  the  necessity  of  keeping 
healthy  cows  in  properly  constructed  and  well-kept  stables,  and 
in  impressing  upon  him  the  fact  that  the  procuring  of  pure  milk 
and  its  proper  handling  constitute  the  fundamental  principles  of 
a  prosperous  development  of  the  milk  industry  in  general,  and 
not  for  the  milk  supply  of  the  city  alone.  Many  farmers,  espe- 
cially the  small  ones,  can  only  be  convinced  by  practical  demon- 
strations of  the  advantages  to  be  derived  from  proper  stabling 
and  care,  and  therefore  it  is  our  duty  to  win  over  reasonable  and 
progressive  farmers  to  the  erection  of  model  dairies,  and  to  offer 
to  the  smaller  farmer  the  aid  and  advice  by  which  he  can  improve 
his  condition  with  the  least  expenditure.  Even  if  nothing  more 
than  diligence,  attention  and  a  feeling  of  responsibility  are  aroused 
these  alone  would  mean  a  tremendous  improvement  over  the  con- 
ditions prevailing  at  the  present  time. 

It  is  evident  that  if  no  special  milk  rooms  are  provided  every- 

152 


Procuring  Sterile  Milk.  153 


thing  should  be  avoided  during  milking  which  would  cause  stirring 
up  of  the  dust,  such  as  removal  of  manure  and  feeding. 

As  long  as  the  milk  gland  is  in  a  healthy  condition  the  cells 
secrete  a  sterile  product,  which  becomes  contaminated  with 
bacteria  only  in  the  lowest  part  of  the  teats,  in  their  ducts,  or 
during  the  process  of  milking,  etc. 

Bacteria  are  always  present  in  the  lowest  parts  of  the  ducts 
of  the  cistern,  as  a  result  of  contamination  from  the  litter.  These 
bacteria  and  also  those  which  fall  into  the  milk  during  milking, 
and  the  massaging  of  the  quarter,  render  the  procuring  of  sterile 
milk  practically  impossible,  even  when  the  strictest  care  is  taken 
to  prevent  as  far  as  possible  the  subsequent  contamination  of 
the  milk. 

In  spite  of  opposing  views,  it  may  be  considered  proved  at 
the  present  time  that  the  milk  in  the  udder  is  sterile  as  long  as 
the  animal  is  not  affected  with  diseases  of  the  udder  or  severe 
general  affections.  Lister,  Miessner,  Escherich,  Kitt,  Tromms- 
dorff,  Eullmann,  Seibold  and  others  succeeded  in  procuring  abso- 
lutely sterile  milk.  This,  of  course,  was  only  in  small  quanti- 
ties, and  drawn  with  special  care,  such  as  washing  the  udder, 
disinfection,  protective  covers,  etc. 

The  first  streams  of  milk  are  of  course  always  contaminated 
with  bacteria  (Schulz,  Luz,  d'Heil) ;  the  subsequent  ones  may  be 
sterile,  but  frequently  they  also  may  contain  bacteria,  as  confirmed 
by  the  works  of  Boekhout,  Ott  de  Vries,  Ward,  Koning,  and 
Freudenreich.  In  practice  the  procuring  of  milk  with  a  moderate 
number  of  bacteria  must  be  considered  satisfactory.  Schulz,  for 
instance,  found  that  the  first  milk  procured  contained  55,566  up 
to  97,240  bacteria  per  c.  c.,  while  during  the  middle  of  the  milking 
it  contained  only  2,070  to  9,985,  and  in  the  last  from  0  to  500 
bacteria.  In  an  interrupted  milking,  that  is,  when  the  milk  was 
obtained  in  four  portions,  Backhaus  and  Appel  counted  in  the 
first  part  170  to  950,  in  the  second  60  to  255,  in  the  third  10  to  70, 
in  the  fourth  0  to  45  bacteria  per  c.  c. 

For  procuring  sterile  milk  the  following  measures  are  recommended: 

Washing  the  udder  with  soap  and  water,  disinfection  with  alcohol  (Kitt,  Kolle)  ; 
disinfection  with  mercuric  chloride  solution  (Fauss,  Klimmer)  ;  mercuric  chloride  solution 
and  rinsing  with  boracic  water  and  formalin  (Boekhout  and  de  Vries)  ;  washing  with 
a  2%  mercuryoxycyanide  soap  (Freudenreich),  followed  with  rubbing  with  sterile  cotton 
(Ostertag) ;  salicylcotton  (Eichert);  sterile  cloths  (Freudenreich);  and  then  after 
cleaning  and  thoroughly  disinfecting  the  hands  of  the  milker  with  soap,  water  and  the 
same  disinfecting  agent  which  has  been  used  for  disinfection  of  the  udder,  the  milk  may 
be  carefully  drawn  by  the  usual  method,  which  is  termed  ' '  fisting. ' ' 

Backhaus  after  a  coarse  cleaning  of  the  udder,  covers  it  with  a  bag  which  con- 
tains disinfecting  fluids.  After  a  short  action  of  the  disinfectant  the  fluid  is  allowed 
to  escape  through  a  stop-cock  attached  at  the  lower  part  of  the  bag  and  the  udder  is 
rinsed  with  previously  boiled  warm  water.  Other  authors  cover  the  body  of  the  animal 
with  sheets,  leaving  only  the  udder  exposed. 

Boekhout,  Ott  de  Vries  and  Trommsdorff  used  sterile  milking  tubes  for  taking 
samples.  In  this  operation  it  is  to  be  regretted  that  even  in  the  most  careful  manipulation 
with  sterile  milking  tubes,  infections  of  the  udder  sometimes  result.  Eullmann  therefore 
prefers  direct  milking.  He  also  rubs  white  paraffin  salve  into  the  skin  of  the  surround- 
ing part  of  the  udder. 


154  Bacteria  in  Market  Milk. 


Through  such  protective  measures  individual  authors  obtained 
the  following  results: 

Freudenreich :     200  to  300  bacteria  per  c.  c. 

Szasz:     2  sterile,  11  with  an  average  of  about  2,700  bacteria. 

Hesse :    1,600  bacteria  per  c.  c. 

Marshall :     295  bacteria  per  c.  c. 

Lux :    0  to  97  to  6,800  bacteria  per  c.  c. 

Kolle:  80  to  15,000;  in  33%  of  the  experiments  the  counts 
wrere  below  300  bacteria  per  c.  c.,  50%  below  500,  others  up  to 
800  per  c.  c.  Only  4.7%  yielded  700  to  800  bacteria. 

Willem  and  Minne :     1  to  5  bacteria  per  c.  c. 

Willem  and  Miele :    0  to  37,  4  to  218  bacteria,  respectively. 

Seibold  studied  the  bacterial  content  of  the  milk  under  the 
most  varied  experimental  methods,  and  especially  under  condi- 
tions which  correspond  most  nearly  to  those  prevailing  in  practice. 

1.  Without  protective  measures. 

2.  After  soaping  the  udder. 

3.  After  soaping  and  disinfecting  with  alcohol. 

4.  After  repeated  disinfection  with  alcohol,  and  procuring 
through  sterile  milking  tubes. 

The  poorest  results  were  obtained,  as  would  be  expected,  by 
the  first  method,  and  the  best  results  by  the  fourth  method,  with 
which  it  was  frequently  possible  to  obtain  completely  sterile 
samples. 

The  number  of  bacteria  by  the  fourth  method  fluctuated 
between  0  and  12,  by  the  third  between  0  and  85,  and  by  the  second 
between  0  and  434  per  c.  c. 

The  first  method  produced  samples  of  milk  with  less  than 
10  up  to  several  thousand  bacteria. 

Trommsdorff  and  Rullmann  observed  in  samples  which  had 
been  procured  without  special  precautionary  measures,  such  as 
cleaning  of  the  udder  and  hands,  on  an  average  (96  samples) 
6,700  bacteria  per  c.  c.,  but  only  1,500  bacteria  when  a  thorough 
cleaning  of  the  udder  and  of  the  hands  of  the  milker  had  been 
undertaken. 

Seibold,  Trommsdorff  and  Eullmann  found  in  individual 
cases  an  enormously  high  bacterial  content  even  in  freshly  pro- 
cured milk,  the  colonies  on  the  plates  containing  mostly  strepto- 
cocci. These  samples  were  obtained  from  cases  of  inflammation 
of  the  udder,  and  the  milk  was  already  contaminated  with 
streptococci  before  leaving  the  udder.  These  organisms  would 
not  otherwise  be  present  in  aseptically  procured  milk  (Seibold). 

^As  it  is  difficult,  even  under  the  strictest  conditions,  to  procure 
sterile  milk,  or  milk  with  a  very  low  bacterial  content,  therefore 
in  the  wholesale  production  of  milk  such  results  are  still  more 
difficult,  and  in  fact  impossible.  The  milk,  immediately  after 
leaving  the  milk  canal,  becomes  contaminated  by  bacteria  which 
have  colonized  there.  Among  the  bacteria  which  may  be  found 


Reduction  of  Bacterial  Content.  155 

in  the  milk  from  animals  free  from  udder  affections,  and  which 
has  been  drawn  under  aseptic  conditions,  the  groups  of  staphy- 
lococci,  colon  bacteria,  Bacillus  subtilis  and  B.  mesentencus  should 
be  especially  mentioned.  Seibold  also  demonstrated  acid-fast 
rods.  Eullmann  and  Trommsdorff  found  no  representative  of  the 
colon  group,  but  they  isolated  staphylococci,  a  few  representa- 
tives of  spore-bearing  species,  and  especially  the  anthracoides 
(mycoides)  species. 

In  ordinary  milk  production  there  also  come  into  consider- 
ation an  army  of  air  and  stable  bacteria,  which  adhere  to  the 
food,  manure  and  litter,  as  well  as  those  which  vegetate,  as 
saprophytes,  on  the  skin  of  cattle,  especially  on  the  skin  of  the 
teats,  and  on  the  hands  of  the  milker,  besides  those  groups  of 
bacteria  which  colonize  with  special  predilection  on  milking 
utensils  and  in  the  cans. 

The  number  and  kind  of  bacteria  found  by  the  different 
authors  vary  to  a  considerable  extent,  depending  upon  the  degree 
of  cleanliness  used  in  obtaining  the  several  samples. 

Dean  found  in  milk — 

From  filthy  cows 9,845  to  17,155  bacteria  per  c.  c. 

From  clean  dry  cows 8,295  to     9,426  bacteria  per  c.  c. 

From  cows  with  dampened  skins    640  to     2,350  bacteria  per  c.  c. 

The  same  work  also  throws  light  on  the  influence  of  the  milk 
vessels.  If  the  milk  was  collected  in  sterile  milk  vessels, 

it  contained 355  to       1,702  bacteria  per  c.  c. 

In  well  cleansed  milk  vessels.  13,080  to  93,420  bacteria  per  c.  c. 
In  dirty  milk  cans 215,400  to  806,320  bacteria  per  c.  c. 

Russell,  in  using  sterile  milk  vessels,  found  165  bacteria  per 
c.  c.  in  freshly  drawn  milk,  while  in  case  of  only  ordinary  cleansing 
there  were  4,625  bacteria  per  c.  c.  in  such  freshly  procured  milk. 
Grotenfeld  counted  in  the  milk  from  well-kept  animals,  in  clean 
stables,  only  106  bacteria  as  compared  with  670,000  per  c.  c.  in 
milk  from  dirty  stables. 

The  kind  of  milk  can  also  has  an  influence.  Backhaus  con- 
siders enamel  cans  as  the  best;  tin  vessels  were  found  to  be 
almost  as  good,  while  milk  vessels  constructed  of  wood  were 
unsatisfactory. 

The  work  of  Koning  shows  the  influence  of  the  bacterial  flora 
of  the  air  on  the  bacterial  content  of  the  milk.  The  author  counted 
500,000  to  700,000  bacteria  in  the  stable  air,  whereas  the  outside 
air  contained  only  90,000  bacteria.  He  found  that  the  volume  of 
air  between  the  cows  was  especially  rich  in  bacteria.  Milk  which 
is  procured  in  the  pasture  contains  fewer  bacteria  than  stable 
milk.  If  it  is  customary  to  change  the  straw  and  also  feed  shortly 
before  or  during  the  milking  time,  these  factors  tend  greatly  to 
increase  the  bacterial  content  of  the  milk. 

If  the  milk  is  subjected  to  the  so-called  " improving  methods" 
of  the  most  varied  kinds,  and  has  to  be  transported  for  long  dis- 


156  Bacteria  in  Market  Milk. 


tances,  it  is  obvious  that  when  it  finally  reaches  the  consumer  it 
must  contain  tremendous  numbers  of  microbes  of  various  kinds. 
The  author  counted  in  the  market  milk  of  Munich  from  13,000 
upwards  to  several  millions  of  bacteria  per  c.  c. 

Milk  offers  to  most  bacteria  which  may  contaminate  it  a 
splendid  culture  medium,  their  multiplication  in  it  depending 
on  the  character  of  the  container  (cans,  flat  or  open  bowls), 
temperature  and  subsequent  treatment. 

Freudenreich,  B.  Meyer,  Cnopf  and  others  conducted  experi- 
ments on  the  influence  of  cooling  on  the  number  of  bacteria,  and 
established  definite  proof  for  the  statement  made  in  practice  that 
immediate  cooling  constitutes  the  best  preserving  agent  for  milk. 

According  to  Cnopf  the  multiplication  at  0  deg.  C.  was  re- 
markably low,  at  12.5  deg.  it  was  4  to  935  times  greater,  and  at 
35  deg.  2,200  to  3,800  times  greater  than  at  0  deg.  C. 

Freudenreich  proved  that  in  milk  which  at  the  beginning  of 
experiments  contained  10,000  (accurately  9,300)  bacteria,  they 
scarcely  multiplied  when  kept  for  three  hours  at  15  deg.,  wThereas 
at  25  deg.  they  doubled,  and  at  35  deg.  they  tripled  in  quantity. 
After  six  hours  at  15  deg.  they  numbered  2.7  times,  at  25  deg. 
18.5  times,  at  35  deg.  about  1,300  times  more  than  the  original 
number,  while  after  nine  hours  the  number  when  kept  at  15  deg. 
was  5  times,  at  25  deg.  108  times,  at  35  deg.  3,800  times  as  numerous 
as  in  the  original  count ;  and  in  24  hours  at — 

15  deg.  C.  the  count  was  5,700,000,  or  613  times 
25  deg.  C.  the  count  was  50,000,000,  or  5,380  times 
35  deg.  C.  the  count  was  570,500,000,  or  61,344  times 

The  author  desires  at  this  place  to  comment  especially  on  the  slight,  and  -somewhat 
problematical  value  of  bacterial  counts,  not  alone  because  the  results  of  the  different 
sowing  and  counting  methods  show  such  enormous  differences,  but  because  the  entire 
system  also  depends  on  a  supposition  of  the  development  of  a  colony  from  a  single 
bacterium  which  was  previously  present,  a  premise  which  is  open  to  very  serious 
objections.  If  it  is  considered  how  many  bacteria  attach  to  tenaciously  adhering 
threads  (sarcina,  streptococci'),  and  how  many  bacteria  possess  a  tendency  to  proliferate 
in  cultural  combinations,  and  to  remain  together  in  the  relatively  sticky  material  of 
milk,  then  it  becomes  apparent  that  the  counted  bacterial  number  represents  but  a  small 
part  of  the  number  of  bacteria  which  are  actually  present  in  the  milk.  Of  course  in 
general  the  number  of  colonies  developing  on  the  plate  represent  a  certain  initial 
point  for  deducing  whether  and  in  what  degree  a  bacterial  growth  has  taken  place  in 
the  milk,  but  it  does  not  indicate  more  than  the  relative  age  of  the  milk,  since  fresh 
milk  may  also  be  rich  in  bacteria,  and  besides  luxuriantly  growing  as  well  as  slowly 
multiplying  bacteria  may  be  present  in  the  milk. 

A  better  method  for  the  establishment  of  the  actual  number  of  bacteria  in  milk  is 
the  one  suggested  by  Skar,  which  consists  of  a  direct  count  of  the  bacteria  in  a  smear 
(see  technique). 

Through  plating  a  certain  impression  is  obtained  of  the  kind 
of  bacteria  occurring  in  the  milk,  and  corresponding  to  the  growth 
of  the  colonies  and  the  morphology  of  the  bacteria  it  is  possible 
to  draw  certain  conclusions  as  to  the  groups  under  which  the 
bacteria  that  are  present  may  probably  be  classified. 

Further  deductions  as  to  whether  the  microbes  should  be  con- 
sidered pathogenic,  and  whether  bacteria  are  present  which  confer 


Thermal   Limits  of   Bacteria.  157 

disease-producing  properties  to  the  milk  through  products  of  de- 
composition, splitting  up  of  proteids,  etc.,  can  only  be  possible 
after  an  accurate  determination  of  all  properties  which  would 
allow  the  recognition  of  the  colony  as  a  certain  species  belonging 
to  a  large  group. 

This  determination  of  the  representatives  of  a  group  is  not  simple,  and  requires 
study  and  continued  experimental  work  of  days  and  weeks  relative  to  fermentation 
qualities,  requirements  of  growth,  pathogenic  properties  on  test  animals,  ferment-like 
characteristics,  etc.  These  experiments  are  only  of  an  optional  value  in  practice  on 
account  of  the  easy  decomposition  of  milk  as  a  food  substance.  Nevertheless  through 
continued  experiments  on  these  problems  valuable  data  and  results  have  been  obtained 
increasing  our  knowledge  of  the  spread  of  typhoid  fever  and  the  methods  for  combating 
this  and  other  diseases. 

Therefore,  it  should  be  aimed  to  prevent  the  entrance  into  the 
milk  of  directly  or  indirectly  injurious  bacteria  by  procuring  the 
milk  in  a  clean  and  careful  manner.  Once  such  bacteria  gain 
entrance  into  the  milk  and  multiply,  their  recognition  and  isola- 
tion are  too  difficult  for  the  practical  inspector  of  milk  to  consider. 

Milk  hygiene  can  produce  practical  results  only  if  it  is  inau- 
gurated at  the  place  of  production. 

The  pathogenic  bacteria  of  diseases  of  animals  and  man  will 
not  be  considered  here,  and  only  brief  consideration  will  be  given 
to  the  army  of  saprophytes  which  gain  entrance  to  the  milk  from 
the  air,  straw,  manure  and  the  milk  vessels. 

Although  from  the  numerous  possibilities  of  infection  of  milk 
a  definite  bacterial  flora  can  hardly  be  expected,  nevertheless,  cor- 
responding with  the  nutritive  material  of  the  milk,  and  the  methods 
employed  in  its  storage  and  transportation,  as  well  as  the  subse- 
quent treatment,  conditions  are  created  which  are  favorable  to 
some  varieties  of  bacteria,  while  for  others  they  are  less  favorable 
or  even  harmful.  Through  the  growth  of  a  certain  kind  of  bacteria 
the  conditions  may  be  changed  in  such  a  way  that  the  require- 
ments of  propagation  for  other  groups  are  produced.  Likewise 
through  symbiosis  conditions  may  be  developed  which  are  re- 
quired by  certain  species  of  bacteria,  or  under  which  certain 
species  may  be  destroyed,  whereas  without  symbiosis  probably 
neither  of  the  species  could  exist,  since  they  are  dependent  upon 
each  other.  The  growth  of  certain  species  is  therefore  dependent 
on  numerous  influences. 

According  to  the  thermal  limits  in  which  bacteria  can  live,  the 
species  may  be  separated  into  those  which  thrive  at  0  deg.  C.  (up 
to  15-20  deg.) :  psychrophile ;  those  which  thrive  at  10-15-40  deg.: 
mesophiles ;  and  finally  into  thermophiles,  whose  thermal  optimum 
ranges  between  40  to  70  deg.  C.,  or  even  higher. 

The  species  of  psychrophile  propagate  even  in  well  cooled 
milk  and  at  low  temperature,  and  at  times  change  its  taste.  Ref- 
erence should  be  made  here  to  the  Bacillus  lactis  saponacei  and 
the  Bacillus  sapolacticum,  which  give  a  soapy  taste  to  the  milk. 
This  defect  of  flavor  is  principally  observed  in  cool  weather,  and 
at  the  beginning  or  end  of  the  winter. 


158  Bacteria  in  Market  Milk. 


Subtilis  varieties,  mycoid  varieties,  vinegar  bacteria,  yeasts, 
Penicillium  glaucum,  mucor  varieties  and  aspergilli  also  grow  from 
0  to  8  deg.  C.,  as  do  soil  bacteria,  fluorescence  varieties  and  bacilli 
which  split  up  proteids  (bitter  taste  of  milk).  According  to 
Kniisel,  psychrophile  bacteria  may  be  demonstrated  in  sterilized 
milk,  while  Bischoff  found  them  in  the  market  milk  of  Leipsic. 

Bischoff  found  that  in  milk  which  had  been  cooled  to  about  0  deg.  C.,  the  bacterial 
number  gradually  diminished  from  the  third  to  the  seventh  day;  it  then  multiplied 
rapidly,  without  showing  a  considerable  increase  in  the  degree  of  acidity.  A  bacterial 
rennet  formed,  however,  and  the  milk  coagulated  on  boiling.  This  appeared  as  early  as 
the  fourth  to  seventh  day,  when  the  milk  was  kept  between  6  and  8  deg.  C.  Frozen 
milk  on  the  other  hand  keeps  for  a  remarkably  long  time. 

Kniisel  found  peptonizing  bacteria  in  sterilized  market  milk  which  had  been  kept 
at  8  deg.  C. ;  as  a  result  of  their  growth  the  milk  had  the  appearance  of  soapy  water, 
and  possessed  a  bitter  taste. 

Therefore,  all  milk  cannot  be  protected  from  spoiling  by  being 
kept  cool.  The  milk  must  be  procured  at  the  start  with  as  small  a 
number  of  bacteria  as  possible. 

The  opposite  of  these  psychrophile  species  are  the  thermo- 
philes,  which  may  be  actually  isolated  from  the  army  of  accom- 
panying bacteria  by  a  high  degree  of  heat.  They  continue  to  grow 
even  in  temperatures  of  70  deg.  C.,  and  over  (Zettnow),  a  tem- 
perature at  which  most  of  the  vegetative  bacteria  and  to  some 
extent  also  spores  of  the  mesophiles  and  psychrophiles  are  de- 
stroyed. Such  bacteria  were  found  not  only  in  hot  springs  by 
Cert'es,  Garrigon,  Karlinski,  Teich,  Tsiklinsky,  but  also  in  river 
water  (Miquel,  Tieghem,  F.  Colin,  MacFadyan  and  Blaxall, 
Michaelis  and  others) ;  finally  they  were  found  almost  everywhere 
by  Globig,  and  in  the  intestinal  content  of  animals,  feces,  manure, 
liquid  manure,  in  the  soil  and  upon  fodder  by  Rabinowitsch. 

The  thermophile  species  are  not  directly  pathogenic.  This 
group,  however,  contains  several  toxin  producers,  and  peptonizers 
of  milk. 

Sporulating  bacteria  which  form  spores  that  resist  a  heat  of 
100  deg.  C.  and  over  should  not  be  confused  with  the  thermophiles. 
(Peptonizing  species,  as  mycoides,  anthracoides,  subtilis,  mesen- 
tericus  and  the  butyric  acid  bacilli).  Between  the  psychrophiles 
and  the  thermophile  bacteria  lie  the  large  army  of  mesophiles,  to 
which  belong  most  of  the  ordinary  species  of  bacteria  found  in 
market  milk. 

Corresponding  to  their  requirements  for  oxygen  they  are 
divided  into  obligatory  aerobes,  which  propagate  only  in  the 
presence  of  oxygen,  facultative  anaerobes,  which  can  vegetate 
without  oxygen,  and  obligatory  anaerobes,  which  can  grow  only  in 
the  absence  of  oxygen. 

They  may  also  be  divided,  according  to  the  substances  which 
they  attack,  into  those  which  split  sugar,  proteids  and  fats,  or, 
according  to  the  products  which  they  form  during  their  growth  in 
certain  media,  into  acid  producers  (lactic  acid  producers,  butyric 
acid  producers,  etc.),  or  into  alkaligenic  species  and  gas  producers, 


Period   of  Incubation. 


alcohol  producers,  bacteria  with  rennet-like  action,  pigment  pro- 
ducers, slime-forming  bacteria,  etc. 

The  varieties  of  bacteria  which  are  found  in  milk  under 
general  conditions  of  production,  even  when  conducted  under 
special  provisions  for  obtaining  clean  milk  with  unusual  precau- 
tionary measures  (provided  that  the  milk  originates  from  healthy 
animals  and  is  drawn  by  healthy  milkers),  are  of  special  interest 
to  the  milk  hygienist. 

These  bacteria  split  sugar  and  proteids,  and  attack  fat.  Ac- 
cording to  Fliigge,  they  are  separated  into : 

1.  Aerobic   lactic   acid   bacteria,   which   cause    spontaneous 
souring  and  do  not  form  spores ; 

2.  The  anaerobic  butyric  acid  bacilli,  and 

3.  The     aerobic     peptonizing     bacteria,     with     remarkably 
resistant  spores. 

These  bacteria,  however,  do  not  propagate  uniformly  well  in 
milk,  but  they  are  subject  to  influences  of  the  medium,  which  really 
constitutes  an  elective  culture  medium  for  some  of  the  species, 
whereas  it  is  destructive  for  others.  The  time  during  which  no 
increase  of  bacteria  can  be  noted  in  milk  is  known  as  the  period 
of  incubation  (Soxhlet).  In  fact  there  may  be  not  only  no  multi- 
plication of  bacteria  in  the  milk,  but  under  certain  conditions  dur- 
ing the  beginning  of  the  incubation  there  may  even  be  a  diminu- 
tion of  the  bacterial  number  which  is  first  found;  the  bacteria 
present  in  the  milk  are  subject  to  the  injurious  influences  of  the 
animal  secretion;  the  milk  is  in  the  germicidal  stage  (Koning). 

'Fokker  in  1890  was  the  first  to  assert  that  raw  milk  (he  used  for  his  experiments 
goat's  milk)  must  have  germicidal  properties.  He  proved  that  raw  milk  when  inoculated 
with  lactic  acid  bacteria  resists  spoiling  for  a  longer  period  than  was  the  case  with 
milk  that  had  been  boiled.  Prior  to  his  investigations  however  Wolffhiigel  and  Eiedel 
found  in  1886  that  cholera  vibrios  readily  multiply  in  boiled  or  sterilized  milk,  whereas 
in  raw  milk  their  growth  is  rapidly  checked.  As  a  result  of  these  findings  the  question  as 
to  whether  milk  possesses  germicidal  properties  became  the  subject  of  dispute.  While 
Freudenreich,  Hesse,  Park,  Cozzolino,  Conn,  Schenk,  Behring,  Eullmann  and  Trommsdorff, 
Eosenau  and  McCoy,  Sassenhagen  and  Bab  claim  that  milk  possesses  inhibiting,  or  even 
destructive  properties  for  bacteria,  Richet,  Hueppe,  Heim,  Friedrich,  Kitasato,  Uffelmann, 
Weigmann  and  Zirn,  Basenau,  Schrank,  Schottelius,  Moro,  Heinemann,  Rubinstein, 
Stocking,  Sommerfeld,  Klimmer,  Knox  and  Schorer,  and  Kuntze  express  their  belief 
against  this  power  in  the  sense  of  the  bactericidal  action  of  blood  serum,  and  think 
that  the  germicidal  properties  exist  only  towards  certain  species  of  bacteria.  They 
also  believe  that-  the  composition  of  the  milk  creates  favorable  conditions  for  the 
propagation  of  some  of  the  bacteria,  while  for  others  this  is  not  the  case,  just  as  with 
elective  media,  some  of  the  less  favored  species  become  injured  or  destroyed  by  the 
multiplication  of  lactic  acid  bacteria  and  their  products. 

The  presence  of  specific  germicidal  substances  (alexins,  ambo- 
ceptors,  leucins)  in  special  kinds  of  milk,  such  as  colostral  and 
mastitis  milk,  has  been  proven  by  the  work  of  Bauer,  Sassenhagen, 
Rullmann  and  Trommsdorff,  whereas  the  question  of  the  occur- 
rence of  these  in  normal  milk  has  not  yet  been  sufficiently  demon- 
strated, although  the  fact  of  a  diminution  of  bacteria  in  freshly 
drawn  normal  milk  has  been  established  by  our  methods  of 
counting. 


Bactei'ia  in  Market  Milk. 


Colostrum : 
1.  2. 

77,000      82,900 
71,000      76,400 


In  order  to  furnish  a  few  examples,  several  experimental 
results  will  be  cited  from  the  work  of  Grimmer. 

Koning  found  in  various  samples  of  freshly  drawn  milk  the 
following  numbers  of  bacteria  per  c.  c. : 

Milk: 
1  2.  3. 

immediately  107,000     143,000      18,510 

after    6  hours 96,000     142,000       16,000 

after  12  hours 74,000      

after  18  hours 120,000     155,000      14,700      56,000 

after  24  hours 13,200      115,000 

after  30  hours 145,000    470,000      13,800      115,000 

after  36  hours 2,050,000      

after  42  hours 490,000    800,000     106,000      >    596,000 

The  slight  diminution  of  the  bacterial  content  of  this  experi- 
mental series  could  of  course  not  be  attributed  to  the  existence  of 
a  specific  germicidal  action,  but  rather  to  errors  in  our  methods,  or 
to  the  elective  action  of  media,  since  the  differences  are  relatively 
slight. 

The  results  are  more  apparent  in  the  tables  of  Eullmann  and  Trommsdorff : 
Keeping  at  room  temperature: 


Teat        Milking 

Imme- 
diately 

1  hour 

2  hrs. 

3  hrs. 

4  hrs. 

5  hrs. 

19  hrs. 

43  hrs. 

fr.  rgt.      beginning 

2,400 

2,100 

2,300 

1,900 

2,100 

2,500 

2,100 

1,200,000 

middle 

1,400 

900 

1,300 

1,600 

1,800 

1,700 

1,300 

1,400,000 

end 

700 

800 

600 

900 

700 

1,100 

700 

500,000 

fr.  1ft.      beginning 

12,000 

900 

9,000 

7,000 

7,000 

9,000 

6,000 

1,000,000 

middle 

16,000 

14,000 

1,800 

1,400 

1,100 

1,600 

1,600 

450,000 

end 

3,000 

1,000 

2,400 

2,400 

3,000 

2,700 

2,200 

1,100,000 

hd.  rgt.     beginning 

200,000 

118,000 

118,000 

10,700 

98,000 

71,000 

33,000 

420,000 

middle 

35,000 

56,000 

37,000 

23,000 

38,000 

28,000 

17,000 

250,000 

end 

13,000 

11,000 

10,000 

5,000 

2,600 

2,400 

900 

1,400,000 

hd.  1ft.     beginning 

7,000 

4,400 

4,600 

7,200 

5,400 

5,600 

7,200 

20,000.000 

middle 

60 

400 

160 

240 

180 

240 

160 

10,000 

end 

3,400 

3,000 

3,600 

2,600 

5,000 

2.200 

2,100 

230,000 

In  special  samples  with  small  bacterial  count  the  comparison  was  still  more  striking: 


Cow  No.    Teat 

At  room 
temperature 

Imme- 
diately 

After 
one  c'ay 

After 
two  days 

After 
three  days 

8         fr.  rgt. 

beginning         |           160 

40 

16,000 

2,000,000 

middle 

80 

40 

18,000 

16,000,000 

end 

40 

80 

17,000,000 

20,000,000 

fr.  1ft. 

beginning 

11.000 

9,000 

8,000 

40,000 

middle 

1,700 

720 

40 

1,200 

end 

1,300 

600 

800 

18,000 

hd.  rgt. 

beginning 

120 

400 

2,500,000 

5,000,000 

middle 

40 

400 

18,000,000 

60,000 

end 

180 

160 

64,000 

5,000,000 

hd.  1ft. 

beginning 

200 

40 

78,000 

5,000,000 

middle 

80 

500 

300,000 

6,500,000 

end 

240 

80 

50,000 

2,500,000 

9         f  r.  rgt. 

600 

360 

2,500,000 

25,000,000 

fr.  1ft. 

40 

80 

43,000 

4,000,000 

hd.  rgt 

450 

500 

2,500,000 

25,000,000 

hd.  1ft. 

40 

240 

9,000,000 

innumerable 

Germicidal  Properties. 


Trommsdorff  and  Rullmann  conclude  from  these  and  other  experiments  that  the 
bacterial  content  of  milk  does  not  increase  at  room  temperature  in  the  first  period 
following  the  milking.  "On  the  contrary  in  some  of  the  samples  inside  of  the  first 
5  to  7  hours  a  pronounced  diminution  of  the  bacterial  number  was  observed,  which  was 
still  more  pronounced  in  the  following  period  so  that  in  a  great  number  of  cases  the 
bacterial  number,  after  1,  2,  and  even  3,  and  in  one  case  even  after  5  days,  was  found 
lower  than  directly  after  the  milking.  Where  there  occurred  no  diminution  in  bacteria 
the  bacterial  content  remained  the  same  as  that  found  after  the  milking,  during  1  to  3 
days. ' ' 

Milk  which  has  been  contaminated  with  numerous  bacteria 
in  the  earliest  periods  after  milking  (dirty  milking,  filthy  ves- 
sels), shows  only  to  a  very  slight  extent  the  germicidal  phase.  At 
37  deg.  C.  the  germicidal  substances  act  more  rapidly,  but  the  dura- 
tion of  the  germicidal  phase  is  shortened  (Koning,  Eullmann  and 
Trommsdorff). 

Heating  the  milk  to  over  70  deg.  C.  destroys  its  germicidal 
properties. 

Bauer  and  Sassenhagen  established  the  absence  of  complement  in  ripe  milk  which 
gives  the  impression  that  in  ripe  milk  the  action  is  elective  in  the  sense  that  the  contained 
substances  constitute  food  for  one  microbe  and  poison  for  another.  Of  course,  it  has 
been  established  for  even  ordinary  kinds  of  bouillon  that,  depending  on  their  composition, 
the  growth  of  certain  bacterial  species  upon  them  has  been  checked  for  a  time  (Basenau). 
The  lecithin  contents  of  raw  milk  must  not  be  left  out  of  consideration;  in  certain 
concentrations  lecithin  exerts  a  strong  inhibitory  action  on  bacterial  growth. 

Finally  the  diminution  of  the  bacterial  content  may  be  only  apparent,  as  the 
bacteria  may  multiply  through  their  sticking  together  in  agglutinated  masses,  thereby 
simulating  a  diminution,  a  view  which  is  supported  also  by  Bab  for  colostral  milk. 

After  the  germicidal  action  of  the  milk  has  worn  off  the 
various  phases  of  decomposition  of  milk  set  in,  beginning  sooner 
or  later,  depending  on  the  original  contamination  of  the  milk. 
Koning  distinguishes  seven  such  phases. 

The  fight  of  the  microbes,  their  harmonious,  or  again  anta- 
gonistic relation  to  each  other,  results  in  a  predominance  of  cer- 
tain species  of  bacteria  in  the  various  phases. 

First  (second  phase  according  to  Koning,  the  first  being  the 
germicidal)  the  proteolytes  split  up  the  proteid  bodies  of  the  milk, 
and  thereby  prepare  the  soil  for  the  acid  producers,  which  domi- 
nate the  further  decomposing  phase  (third  phase  according  to 
Koning) ;  the  milk  coagulates.  In  the  fourth  phase  the  alkali  pro- 
ducers partly  neutralize  the  acid  again  by  further  splitting  up  the 
albumoses  of  the  acid  milk  with  the  formation  of  ammonia.  Pep- 
tonized  casein  is  also  attacked.  The  principal  representative  of 
this  decomposing  phase  is  the  Bacillus  fcecalis  alkaligenes  (Gram 
negative,  no  gas  formation,  no  indol,  no  spores,  colors  litmus  milk 
blue).  Through  neutralization  of  the  lactic  acid,  certain  lactic  acid 
bacteria,  Bacillus  acidi  paralactici,  Bacillus  acidi  Ifsvolactici  and 
Micrococcus  acidi  paralactici  liquefaciens,  again  regain  predomi- 
nance (fifth  phase). 

Up  to  this  stage  the  higher  fungi  have  played  a  subordinate 
part,  although  they  may  have  multiplied ;  now  they  appear  in  great 
masses.  The  degree  of  acidity  does  not  hinder  their  growth.  The 
11 


162  Bacteria  in  Market  Milk 


Oidium  lactis  participates  principally  in  the  sixth  phase  of  decom- 
position, although  other  varieties  of  moulds,  penicillia,  and  mucors 
may  also  play  a  part.  The  degree  of  acidity  being  diminished  by 
the  oidium,  bacteria  of  the  fifth  phase  again  commence  to  multiply, 
until  the  seventh  phase  is  inaugurated  through  the  growth  of  the 
anaerobic  butyric  acid  bacilli.  According  to  Koning  this  phase  is 
reached  at  room  temperature  on  about  the  eighth  day. 

Grasberger  and  Schattenfroh  designate  ;the  principal  representative  of  this 
bacterial  group,  the  Bacillus  saccharobutyricus  immobilis  llquefaciens,  a  bacillus  which 
is  large,  thick  and  stubby,  stains  after  Gram,  and  forms  spores  which  are  located  either 
centrally  or  at  the  end  of  the  bacillus.  According  to  Burri  the  bacillus  may  be  most 
readily  isolated  by  boiling  the  milk  for  several  minutes,  and  allowing  it  to  ferment  at 
37  deg.  C.  Besides  this  butyric  acid  ba-cillus,  other  motile  forms  or  bacteria  related 
to  the  first  group  may  be  found. 

The  seventh  phase  finally  passes  into  the  eighth,  in  which  the 
milk  changes  into  a  stinking  putrid  fluid,  in  which  the  decomposi- 
tion of  the  food  material  is  completed  by  the  proteus,  subtilis, 
Bacillus  fluorescens,  and  Bacillus  mesentericus,  besides  mould 
fungi. 

Of  these  phases  of  decomposition  of  milk  the  first  three,  espe- 
cially the  second  and  possibly  the  beginning  of  the  third  phase,  are 
the  most  important. 

In  these  two  phases  the  proteolytes  and  the  rennet  formers 
are  the  first  to  multiply,  causing  a  partly  visible  precipitation  of  the 
casein,  but  subsequently  again  dissolving  it;  further,  the  precipi- 
tated protein  is  immediately  partly  dissolved  when  the  dissolving 
tryptic  ferment  is  present  to  excess.  Weigmann  collects  these 
bacteria  under  the  name  of  casease  bacteria.  On  account  of  their 
properties  of  producing  peptones  from  proteid  bodies  they  are 
called  peptonizing-  bacteria.  Most  of  them  liquefy  gelatin/  The 
group  of  casease  bacteria  includes  a  great  number  of  forms  of 
bacteria,  for  instance : 

Staphylococci,  small  spherical  bacteria  which  occur  ubiquitously  and  in  smears 
from  cultures  appear  as  grape-like  conglomerates.  They  stain  by  Gram 's  method.  They 
grow  from  0  deg.  to  about  40  deg.  C.,  and  frequently  form  at  15  to  20  deg.  and  over, 
yellowish  orange,  or  lemon-yellow  colored  colonies.  At  a  low  temperature  the  casease 
enzymes  are  especially  active.  In  gelatin  stab  cultures  Staphylococci  first  develop  a 
nail-like  growth;  the  liquefied  gelatin  may  then  dry  and  at  the  point  of  the  stab  a 
bell-shaped  air  vesicle  forms,  or  the  liquefaction  may  progress  rapidly  and  a  cloudy 
layer  of  liquid  with  a  sediment  of  Staphylococci  stands  above  the  solid  gelatin. 

In  gelatin  plates  the  small  round  colony  drops  into  a  cup-shaped  depression  which 
also  results  from  the  drying  of  the  liquefied  gelatin.  Besides  the  formation  of  albumose 
and  peptones  the  milk  sugar  is  split  up ;  Lohnis  therefore  classifies  these  organisms  with 
the  lactic  acid  bacteria. 

The  growth  of  sarcina,  which  collect  into  two,  four  or  eight  members,  etc.,  is 
similar,  thereby  forming  bacterial  clumps  of  certain  forms.  They  are  also  Gram-positive. 

On  account  of  their  occurrence  even  in  milk  drawn  in  the  most  cleanly  manner,  their 
presence  in  the  udder  was  accepted,  and  as  a  matter  of  fact  pathogenic  organisms  do 
occur  in  the  group  of  Staphylococci,  which  produce  inflammations  of  the  udder.  Ordinarily 
however,  they  only  inhabit  the  milk  duct. 

The  putrefactive  representatives  of  the  proteus  varieties  should  be  classified 
among  the  non-spore  bearing  casease  bacteria.  They  manifest  many  forms  of  growth, 
and  include  the  following  representatives:  Proteus  sopfii,  zerikeri,  vulgaris,  mirabilis, 
and  fluorescens. 


Putrefactive  Bacteria.  163 


They  are  rod-shaped  bacteria,  motile,  non-spore  bearing,  and  Gram-negative.  The 
forms  of  colonies  and  characteristics  are  quite  variable,  sometimes  showing  root-like 
extensions,  and  at  other  times  branching  outshoots. 

The  most  important  spore-forming  proteolytes  originate  from  forage,  hay,  stable 
dust  and  the  stable  air,  and  are  collected,  under  the  name  of  potato  bacilli,  hay  bacilli 
and  root  bacilli. 

They  are  small  rods  up  to  the  size  of  the  anthrax  bacillus,  with  central  or  terminal 
spores,  and  are  Gram-positive. 

They  grow  best  under  aerobic  conditions. 

Gelatin  is  liquefied,  milk  is  precipitated  as  if  by  rennet,  and  is  then  dissolved. 
In  these  instances  the  rennet  action  is  at  times  more  prominent,  at  other  times  the  action, 
of  the  caaease  appears  more  prominently. 

On  solid  media  the  colonies  have  either  a  wrinkled,  slimy  appearance,  or  they  are 
dry,  with  a  fine  map-like  drawing  on  their  surface;  again  they  may  appear  like  dull 
glass,  gray,  grayish-white,  yellowish  to  brownish,  delicate  and  profuse.  On  the  borders 
of  the  culture  branch-like  shoots  or  ' '  forms  of  Medusa  heads ' '  similar  to  the  cc  lonies  of 
anthrax  (anthracoid  varieties)  may  be  seen. 

The  more  important  forms  are: 

The  Bacillus  mesentcricus  vulgatus;  the  potato  bacillus  (fuscus,  graveolens,  ruber) ; 
Bacillus  liodermes;  Bacillus  subtills  (hay  bacillus)  ;  the  mycoid  varieties;  the  anthracoid 
varieties,  Bacillus  ramosus,  implexus,  radicosus,  tumescens,  megatherium,  tyrotJirix,  etc. 

In  fluid  media  they  generally  form  prolific  wrinkled  membranes;  at  times  they 
cloud  the  bouillon  or  they  may  grow  in  long,  stringy  filamentous  masses. 

Some  of  the  varieties  also  form  butyric  acid ;  thus  for  instance  the  Bacillus 
mesentericus  changes  lactic  acid  into  butyric  acid.  To  this  class  some  of  the  mycoid 
varieties  belong,  for  instance  the  Bacillus  butyricus  Hueppe  and  the  Clostridium  polymyxa. 

Through  the  growth  of  these  and  similar  forms,  the  formation 
of  albumose  and  peptones  develops,  and  the  further  decomposi- 
tion of  the  proteid  substances  is  carried  out,  if  possible,  with  the 
production  of  end  products  such  as  leucin,  tyrosin,  ammonia,  car- 
bonic acid,  indol,  skatol,  methylmerkaptan,  sulphureted  hydrogen, 
toxic  toxalbumins,  and  ptomaines. 

For  the  judgment  of  milk  which  is  considerably  contaminated 
with  bacteria  from  litter  and  forage  the  increased  presence  of  such 
bacteria  is  of  special  importance,  since  most  of  them  form  spores 
which  are  not  always  destroyed  at  the  temperature  of  100  deg.  C. 
and  higher. 

The  Bacillus  prodigiosus,  Bacillus  fluorescens  liquefaciens, 
Bacillus  amylobacter,  and  Bacillus  putrificus  Bienstock,  may  also 
split  up  proteins.  Their  products  vary. 

The  bacterial  substances  which  dissolve  proteins  and  split 
them  up,  exert  their  action  especially  in  neutral  and  alkaline  ma- 
terial, and  they  are  therefore  hindered  in  their  action  by  the  pro- 
ducts of  the  third  phase,  the  second  decomposing  phase. 

The  lactic  acid  producers,  however,  proliferate  only  after 
the  necessary  requirements  for  their  propagation  have  been  created 
by  the  activity  of  the  peptonizing  bacteria. 

Through  the  activity  of  the  lactic  acid  bacteria  the  milk  sugar 
and  other  varieties  of  sugar  are  fermented  to  dextro-rotary  (ro- 
tates plane  of  polarization  to  right)  lactic  acid,  inactive  lactic  acid, 
and  levo-rotary  (rotates  plane  of  polarization  to  left)  lactic  acid, 
depending  on  the  species  of  bacteria  or  the  conditions  under  which 
the  special  species  prevail. 

The  splitting  of  lactose  C^H^O,,  is  accomplished  by  an  inverting  bacterial  enzyme, 
the  lactase,  through  the  introduction  of  water  whereby  it  is  converted  into  2C6H12O6 
known  as  D-glucose  and  D-galaetose,  which  by  further  splitting  break  up  into  4C3H6O3. 


164  Bacteria  in  Market  Milk. 


The  lactic  acid  yield,  however,  corresponds  even  in  the  extreme 
cases  only  to  about  98%  of  the  contained  milk  sugar,  as  in  the  mean- 
time, depending  on  the  variety  of  the  lactic  acid  producers,  the 
lactic  acid  itself  is  again  broken  up  into  simpler  acids,  acetic  acid, 
valerianic  acid,  succinic  acid,  and  carbonic  acid;  alcohol,  aldehyde 
and  possibly  hydrogen  result  besides  the  lactic  acid. 

In  spontaneously  coagulated  milk  mostly  inactive  lactic  acid 
is  found,  or  a  mixture  of  inactive  and  dextro-rotary  lactic  acid ;  but 
only  in  exceptional  cases  is  pure  dextro-rotary  lactic  acid  found 
(Gunther  and  Tierf elder).  Kozai  mostly  found  only  the  dextro- 
rotary  polarizing  form. 

The  lactic  acid  bacteria  may  also  be  considered  as  ubiquitous 
micro-organisms ;  they  have  been  found  in  straw,  hay,  fodder,  dust, 
feces  and  in  the  air.  Proliferating  in  milk  they  soon  adapt  them- 
selves to  the  nutritive  medium  which  at  first  is  not  quite  suitable 
for  their  propagation,  and  finally  they  form  standard  varieties  for 
which  the  milk  is  especially  adapted.  Through  continued  growing 
a  weakening  of  the  acid  forming  qualities  may  develop,  and  the 
coagulation  of  the  milk  may  not  take  place  in  spite  of  their  growth, 
the  bacteria  having  become  "milk  tired."  Under  these  conditions 
they  may  show  other  properties,  the  bacteria  rendering  the  milk 
slimy  instead  of  sour,  which  is  known  to  be  the  case  with  some  of 
the  lactic  acid  streptococci. 

The  specific  lactic  acid  bacteria  are  aerobes,  or  facultative 
anaerobes. 

Lohnis  separates  the  specific  lactic  acid  bacteria  into  four  col- 
lective groups: 

1.  Streptococci. 

2.  Plump  short  rods. 

3.  Slender,  long,  lactic  acid  bacilli. 

4.  Micrococci  and  staphylococci. 

The  most  frequent  of  these  are  the  representatives  of  the 
streptococcus  group.  Arranged  into  wreath-like,  shorter  or  longer 
bodies,  the  individual  members  are  characterized  by  coccus  or  oval- 
shaped  bodies.  On  artificial  media  they  frequently  manifest  vacuo- 
lar  degenerative  forms  which  change  the  individual  microbes  to 
the  size  of  bacilli.  Frequently  pure  diplococcic  forms  may  be  found 
which  at  their  ends  are  mostly  pointed  in  a  lancet  shape.  Strepto- 
cocci grown  in  milk  are  composed  of  individual  members  mostly 
in  the  shape  of  a  figure  "8"  which  lie  with  their  long  axis  in  the 
direction  of  the  chain  proving  them  to  be  streptococci  that  entered 
the  milk  after  its  secretion  as  compared  with  the  forms  from  the 
udder.  Some  of  the  representatives  form  capsules  but  only  under 
special  cultural  conditions,  as  for  instance  in  blood  medium,  while 
in  other  media  capsule  formation  appears  to  be  a  constant  charac- 
teristic and  occurs  especially  in  old  milk  cultures. 

Most  of  the  streptococci  are  Gram-positive.  They  possess  no  motility  and  form  no 
spores.  On  solid  media  the  colonies  usually  remain  delicate  and  small;  in  fluid  media 


Streptococci. 


165 


Fig.  24. 


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the  growth  takes  place  either  with  general  clouding,  or  with  the  formation  of  flakes  and 
tufts  and  the  bouillon  then  remains  clear.  The  optimum  temperature  of  the  growth  lies 
between  10  and  42  deg.  C.  Most  of  the  varieties  are  facultative  anaerobes. 

Coagulation  of  milk  may  take  place  with  acid  formation,  or  in  spite  of  acid 
formation  it  may  not  coagulate,  or  again  coagulation  may  take  place  with  only  slight 
acid  formation,  which  in  all  probability  depends  on  the  formation  of  substances  having 
the  properties  of  rennet. 

Gas  formation  has  never  been  observed  by  the  author,  but  it  is  supposed  to  occur; 
slime  formation  is  typical  of  some  of  the  species. 

Lohnis  classifies  the  varieties  of  streptococci  found  in  milk  as: 

1.  Those  which  coagulate  milk  and  form  gas:     Micrococcus  sornthali  (Adametz), 
Streptococcus  "a"  from  Kefir   (Freudenreich),  Streptococcus  memelcnsis  (Leichmann), 
Streptococcus  caucasicus   (Migula). 

2.  Those  which  coagulate  milk  but  form  no  gas:     Streptococcus  guntlieri,  Bacillus 
lacticus  Kruse,  Bacillus  lactis  Lister,  Lactococcus  'beijerink,  Bacillus  acidi  lactici  Groten- 
feld,  and  the  streptococci  from  Armenian  buttermilk. 

3.  Those  which  neither  co- 
agulate    milk     nor     form     gas : 
Streptococcus  Jcefir,  Streptococcus 
"~b"  Freudenreich,  Streptococcus 
soya. 

4.  Those  which  neither  co- 
agulate milk  nor  form  gas:  some 
streptococci    of    cheese,    Strepto- 
coccus inocuus. 

5.  Those     which      form 
slime ;     some     varieties     of     the 
Streptococcus  pi/ogenes,  leuconos- 
toc   varieties,    Streptococcus   liol- 
landicus,  Bacterium   lactis   longi, 
"sticky  milk"  producers,  Micro- 
coccus   mucilaginosus,   Bacterium 
lactis  acidi. 

6.  Those  which  in  culture 
form  vine  or  tongue-like  shoots. 

7.  Those      which      liquefy 
gelatine. 

It  is  well  known  that  the 
cultural  characteristics  of  the 
streptococci  may  readily  change : 
a  strong  acid  forming  variety 
may  lose  this  characteristic  by 
long  cultivation  in  milk,  and  may 
become  a  slime  producing  variety, 
so  that  the  distinguishing  feature 
is  not  absolute.  There  are  transi- 
tory forms  between  one  and  the 

other  type,  and  one  type  at  some  time  may  change  into  another  type  by  changing  its 
characteristics. 

Some  varieties  also  belong  to  those  streptococci  (collective  name  streptococcus  or 
Bacterium  lactis  acidi  Leichmann),  which  produce  volatile  substances  and  alcohol  from 
milk  sugar  and  which  at  the  moment  of  their  development  unite  into  a  fragrant  substance, 
a  so-called  fruit  ester,  which  reminds  one  of  the  odor  of  a  certain  fruit  or  fruits;  other 
representatives  of  this  variety  produce  other  substances  with  odor  and  taste,  which  may 
be  described  as  straw-like,  sorrel-like  and  especially  malt-like.  The  author  never  succeeded 
in  producing  striking  odoriferous  substances  in  sterile  milk  with  the  streptococci  cultures 
at  his  command.  He,  however,  does  not  wish  to  refute  from  his  few  experiments  with 
about  20  strains  from  various  provinces,  the  possibility  of  the  production  of  special 
odoriferous  substances  by  the  Streptococcus  lacticus. 

Under  certain  conditions  tremendous  quantities  of  streptococci 
may  occur  in  market  milk  from  cows  which  are  affected  with  strep- 
tococcic  mastitis.  Special  reference  has  been  made  in  the  chapter 
on  affections  of  the  udder,  regarding  the  similarity  of  these  patho- 


-  :•<      - 
-          "  r 


Slreptococcits  lacticus.      1  X  1000. 


166 


Bacteria  in  Market  Milk. 


[Fig.  25. 


genie  varieties,  to  the  probably  harmless  varieties  of  lactic  acid 
producers. 

The  collective  group  of  the  Bacterium  acidi  lactici  is  the  second 
of  importance  in  the  lactic  acid  group  and  is  also  invariably 
represented  in  milk. 

While  the  streptococci  produce  dextro-rotary  lactic  acid,  among  the  representatives 
of  Bacterium  acidi  lactici  there  are  those  which  produce  levo-rotary  lactic  acid. 
Since  the  growth  of  both  species  of  bacteria  depends  on  the  temperature  and  the  method 
of  keeping  the  milk  (in  a  shallow  bowl  or  in  a  deep  vessel),  therefore  under  certain  con- 
ditions whereby  the  Bacterium  acidi  lactici  has  better  chances  for  vegetating  (aerobe, 
optimum  at  about  37  deg.),  it  produces  levo-rotary  lactic  acid  and  in  soiling  in  deep 
vessels  (the  Streptococcus  lactis  acidi  is  a  facultative  anaerobe  and  grows  well  at  20  deg.) 
it  produces  dextro-rotary  lactic  acid.  These  results  have  been  confirmed  by  the  observa- 
tions of  Conn  and  Esten.  The  findings  of 
Heinemann,  Thiele  and  Holling  that  at  incuba- 
tor and  room  temperature,  in  milk  drawn  under 
specially  clean  conditions,  ' '  d-lactic  acid ' '  is 
formed  only  at  the  beginning,  are  of  interest. 

Against  the  practical  utilization  of  these 
observations,  namely  the  conclusion  that  the  ex- 
clusive presence  of  dextro-rotary  lactic  acid  is 
dependent  on  the  specially  clean  procurance  of 
the  milk,  are  the  investigations  of  Pere  and 
Harden,  who  claim  that  the  nature  of  the 
acid  formed  depends  not  only  on  the  producer 
but  also  in  the  case  of  the  same  producer  on 
the  character  of  experimental  procedure;  thus 
for  instance  one  and  the  same  strain  of  Bac- 
terium coli  produced  lactic  acid  showing  opti- 
cally different  properties  when  cultivated  under 
different  conditions,  aerobically  or  anaerobi- 
cally,  etc. 

The  Bacillus  acidi  lactici 
(Hueppe)  group  also  does  not  rep- 
resent constantly  uniform  species, 
but  it  is  a  collective  name  which 
unites  all  bacteria  with  especially 


Representatives  of  the  coli-aerogenes  Strong  acid  forming  properties  that 
group,  from  a  culture.  1  X  800  (Bac-  Ipovi  toward  <3  tllP  Polon  and  P^TIP- 
tcrium  plilcgmasiac  ubcris,  after  Kitt.)  -ledll  L  clHU 

cially  to  the  aerogenes  species. 

The  Bacterium  acidi  lactici  Hueppe  and  the  Bacillus  pneumonia?  Friedlander  are 
similar  to  the  coli-aerogenes  species.  They  are  plump,  mostly  Gram-negative,  from  cocci 
to  short  rods  in  appearance,  forming  individually  longer  rods  and  short  thread-like 
filaments;  they  grow  luxuriantly,  forming  moist  or  almost  dry  indented  colonies  with  a 
slimy  or  jelly-like  consistence.  In  dextrose  media  usually  a  strong  acid  formation 
takes  place.  On  potatoes  the  growth  is  either  luxuriant  with  gas  bubbles,  or  brownish 
and  thin,  or  transparent.  The  odor  varies,  being  either  disagreeable  or  pleasant,  or  at 
times  even  odorless.  From  this  description  it  may  be  seen  that  a  great  number  of 
bacteria  are  united  in  this  group  which  are  classed  by  Lohnis  as  follows: 

1.  Type  of  the  Bacillus  acidi  lactici  Hueppe. 

Gas  formation  with  milk  coagulation.  To  these  belong  the  Bacillus  aerogenes, 
Bacillus  "a"  Guillebean,  Bacillus  "b"  Freudenreich,  Bacillus  laevolacticus,  Bacillus 
acidi  lactici  Gortenfeld,  also  the  lactic  acid  bacilli  of  Fokker  and  others  which  possess 
differing  characteristics,  as  for  instance  the  formation  of  esterlike  odors,  cheesy  odors,  etc. 

2.  Milk   coagulation  without   gas   formation.      Bacillus   Umbatum    (acidi   lactici) 
Marpmann,  without  special  tendency  to  deep  growth.     Bacillus  acidi  aromaticus,  Bacillus 
granulosum,  crenatum,  spirans  and  ramificans   (Weiss)   and  others. 

3.  Gas  formation  without  coagulation   of  milk,  producing  white,   circumscribed, 
hemispherical  colonies,  as  for  instance  the  Bacillus  pneumoniae  Friedlander. 

4.  Neither  gas  formation  nor  coagulation. 


Cheese  Bacteria. 


5.  Neither   gas  formation  nor  coagulation,  but  slime  formation  is  present,  for 
instance  the  Bacillus  capsulatus,  Bacillus  viscosus,  Bacillus  capsulatus  mucosus,  Bacillus 
lactis  pituitosi,  Bacterium  ozacna. 

6.  The  tendril-shaped  colony  forming  Bacillus  aerogenes  capsulatus. 

7.  Without  gas  formation,  but  with  liquefaction,  for  instance  the  Pneumobacillus 
liquefaciens  bovis. 

A  decisive  separation  of  these  types  cannot  be  strictly  ac- 
complished anywhere  in  the  entire  group.  Each  type  has  indi- 
vidual or  several  representatives  which  show  transitory  tendencies 
towards  one  or  the  other  group,  and  the  entire  group  is  closely  re- 
lated to  the  colon  aerogenes  group,  but  in  the  latter,  there  are  no 
such  pronounced  lactic  acid  formations.  The  colon  group  is  motile, 
the  aerogenes  group  non-motile.  While  the  colon  bacilli  form  indol 
and  split  up  proteids,  these  properties  are  absent  in  the  aerogenes 
group.  Milk  is  coagulated  with  gas  and  acid  formation,  in  which 
the  casein  usually  remains  on  the  surface  of  the  pressed-out  serum 
in  the  form  of  a  spongy  coagulum.  The  milk  receives  at  the  same 
time  an  unpleasant,  slightly  offensive  odor,  and  a  salty,  bitter  taste. 
Some  varieties  change  the  milk  in  this  manner  without  the  special 
changes  being  perceptible.  The  several  groups  adapt  themselves 
very  rapidly  to  their  surrounding  conditions,  for  instance  to  the 
cultivation  on  cabbage  or  turnip  media,  and  when  transferred  to 
milk  they  impart  to  these  the  well-known  changes  of  taste. 

Both  bacteria  are  found  in  the  intestines  of  sucklings 
(Escherich). 

It  is  an  important  fact  that  most  bacteria  of  this  group  are 
destroyed  in  a  short  time  at  65  deg.  C.,  so  that  their  occurrence 
in  pasteurized  milk  (in  bottle  pasteurization)  may  be  an  indication 
that  the  heating  to  which  the  milk  has  been  subjected  was 
insufficient. 

According  to  De  Jong  and  Graaf  some  varieties  of  the  colon 
group  resist  heating  to  70  deg.  C.  for  a  short  time. 

The  slender  "cheese  bacteria"  of  the  third  group  of  the  lactic 
acid  producers  are  again  divided  into: 

1.  Those  coagulating  milk  with  gas  formation,  for  instance 
Bacterium   casei    (Freudenreich),    Bacillus    caucasicus    of   Kefir 
(Freudenreich) ; 

2.  Those  coagulating  milk  but  with  no  gas  formation; 

3.  Those  producing  gas  but  no  coagulation ; 

4.  Those  showing  neither  of  these  characteristics; 

5.  Those  producing  slime; 

6.  Those  growing  in  tendril-shaped  colonies. 

The  bacteria  of  this  third  group  are  almost  invariably  non- 
motile,  and  sporeless,  mostly  without  capsules.  They  are  Gram- 
positive.  The  fermentation  of  sugar  varies.  In  milk  they  mostly 
form  levo-rotary  lactic  acid,  while  the  other  two  varieties  are  rarely 
produced.  Some  peptonize  proteids ;  their  growth  is  favored  more 
by  aerobic  than  by  anaerobic  conditions. 


Bacteria  in  Market  Milk. 


The  bacteria  do  not  grow  well  in  milk  but  they  are  found  in 
cheese,  in  the  oriental  varieties  of  sour  milk  and  in  sour  food. 
These  bacteria  are  of  only  slight  importance  in  the  ordinary  lac- 
tic acid  fermentation.  They  prefer  higher  temperatures  and  pro- 
duce fermentation  only  in  the  absence  of  oxygen,  although  their 
growth  is  prolific  even  in  the  presence  of  oxygen. 

As  representatives  of  this  group  the  Bacillus  panis  fermentati 
occurring  on  sour  bread  should  be  mentioned,  and  the  Bacillus 
delbrucki  found  on  sour  food. 

Some  representatives  of  these  "cheese  bacteria"  are  capable 
at  high  temperature  (40-50  cleg.  C.)  of  producing  and  withstanding 
large  quantities  of  lactic  acid,  up  to  1.5%,  and  even  to  2  to  2.5%. 

Lohnis  classifies  the  staphylococci  as  the  fourth  most  widely 
distributed  bacterial  group  of  the  lactic  acid  producers,  but  on  ac- 
count of  their  peptonizing  characteristics  they  might  better  be 
considered  with  the  casease  bacteria  of  Weigmann.  Their  proper- 
ties have  already  been  described  during  the  discussion  of  bacteria 
of  the  first  decomposing  phase.  The  staphylococci  may  also  be 
separated  into : 

(a)  Those  coagulating  milk  and  liquefying  gelatin. 

(b)  Those  which  only  liquefy  gelatin. 

(c)  Those  which  only  coagulate  milk. 

(d)  Those  which  posses    neither    of   these    properties, 

nor  form  slime,  produce  gas,  nor  form  tendrils. 

The  species  mentioned  by  no  means  exhaust  the  number  of  species  and  groups 
which  are  capable  of  producing  lactic  acid.  Thus  the  anthrax  bacillus  splits  up  sugar 
and  starch  into  lactic  acid,  and  also  forms  acetic  acid  (Napias),  and  formic  acid 
(Iwanoff).  Feinberg  demonstrated  for  the  diphtheria  bacillus  the  capability  of  splitting 
up  milk  sugar  with  the  formation  of  alcohol,  aldehyde  and  volatile  as  well  as  non-volatile 
acids.  The  bacillus  of  malignant  edema,  according  to  Kerry  and  Frankel,  in  the 
anaerobic  fermentation  of  grape  sugar,  produces  ethyl  alcohol,  formic  acid,  butyric  acid 
and  lactic  acid ;  cholera  vibrios  and  related  organisms  form  lactic  acid ;  for  instance 
the  vibrio  of  Asiatic  cholera,  the  Vibrio  proteus  (Finkler  and  Prior),  Vibrio  ma-ssauah, 
vibrio  danubicvs  and  others  form  levo-rotary  lactic  acid,  the  vibrio  of  Deneke  forms 
dextro-rotary  and  Vibrio  berolinensis  produces  an  inactive  lactic  acid.  The  formation  of 
these  lactic  acids,  however,  does  not  depend  on  the  bacillus  alone. 

The  Oidium  lactis,  a  milk  mould,  and  others,  are  also  capable 
of  producing  lactic  acid  from  milk  sugar.  Some  of  the  lactic  acid 
forming  varieties  are  rare  in  milk,  others  may  accustom  themselves 
to  milk  so  rapidly  that  they  form  the  typical  acidifying  flora,  the 
presence  of  which  under  certain  conditions  may  be  desirable  since 
by  their  multiplication  the  vegetation  of  the  harmful  peptonizing 
bacteria  and  of  the  producers  of  butyric  acid  is  inhibited. 

With  this  we  leave  the  most  important  varieties  of  bacteria 
which  are  responsible  for  the  normal  spoiling  of  milk,  and  will 
briefly  discuss  those  varieties  of  microbes  belonging  to  the  bacte- 
riology of  milk  and  milk  production  which  always  occur  in  market 
milk. 

Milk  also  invariably  contains  butyric  acid  bacilli.  Their  pre- 
dominance is  inhibited  by  the  lactic  acid  fermentation. 


Butyric  Acid  Bacilli. 


169 


The  specific  butyric  acid  bacilli  are  obligatory  anaerobic  or 
facultatively  anaerobic,  that  is  they  thrive  best  in  the  absence  of 
oxygen ;  there  are,  however,  aerobic  bacteria  which  are  capable  of 
forming  butyric  acid,  for  instance  several  of  the  above-mentioned 
peptonizing  varieties,  the  hay  and  potato  bacilli,  which  without 
specially  attacking  the  milk  sugar,  form  butyric  acid  from  the 
products  of  the  split  proteids. 

The  individual  varieties  show  varying  properties  toward  the  different  kinds  of 
sugars,  as  well  as  toward  the  formed  by-products,  as  butyl  alcohol,  isobutyl  alcohol, 
formic  acid,  acetic  acid,  propionic  acid,  valerianic  acid,  carbonic  acid,  hydrogen,  etc. 

The  obligatory  butyric  acid  producers  are  rods,  chains  or  threads,  with  either  a  plump 
or  a  slender  form;  they  possess  oval  or  roundish  polar  or  central  spores.  The  bacteria 

Fig.  26. 


Blackleg  bacilli.      1  X  1200. 
(After  Friedberger  &   Frbhner.) 

frequently  form  so-called  clostridium  forms,  and  especially  in  starch-containing  media 
they  take  up  granulose;  therefore  certain  parts  of  their  body  or  even  the  entire  bacillus 
may  be  stained  blue  with  iodide  of  potassium. 

The  representatives  of  this  group  are  known  to  pathologists 
as  producers  of  blackleg,  gaseous  phlegmons,  malignant  edema, 
bradsot,  botulism,  and  tetanus.  These  bacilli  at  times  are  capable 
of  energetically  forming  butyric  acid,  and  at  other  times  less  in- 
tensively; at  the  same  time  peptonizing  ferments  (tryptic)  are 
formed,  which  become  active  in  the  absence  of  acid. 

Generally  motile  and  non-motile  forms  of  butyric  acid  bacilli 
are  distinguished  in  milk.  The  latter  form,  of  the  granular  Bacillus 
saccliarobutyricus  is  considered  by  Grasberger  and  Schattenfroh 
as  a  developing  form  of  the  motile,  spore-forming  variety  which 
takes  up  granulose,  forms  toxins,  and  attacks  lactic  acid. 

According  to  their  properties  they  may  be  divided  into  those 
which  form  butyric  acid  principally  from  certain  carbohydrates, 


Bacteria  in  Market  Milk. 


as  for  instance  the  blackleg  bacillus,  the  non-motile  butyric  acid 
bacillus  (Grasberger  and  Schattenfroh),  and  the  bacillus  of  gaseous 
phlegmons  (Frankel).  The  others  are  producers  of  putrefaction 
and  split  up  the  proteids  into  forms  from  which  volatile  fatty  acids 
develop. 

Obligatory  fat-splitting  bacteria  may  also,  although  less  fre- 
quently, be  found  in  milk,  as  for  instance  the  Bactridium  lipolyti- 
cum  (Huss),  through  the  growth  of  which  the  milk  acquires  a  rancid 
taste.  The  Bacillus  fluorescens,  Bacillus  prodigiosus  and  others, 
for  instance  certain  mould  fungi,  may  also  produce  fat-splitting 
enzymes. 

Actinomyces  form  the  transition  organisms  which  lead  from 
bacilli  to  higher  fungi.  These  fungi  form  long  threads  with  true 
branchings.  Widely  distributed  on  grasses  and  especially  grain,  as 
well  as  in  the  soil,  they  are  of  course  also  contained  in  manure  and 
litter,  and  may  occur  in  milk  and  milk  products,  butter  or  cheese, 
and  multiply  therein. 

As  is  the  case  with  all  milk  bacteria,  among  the  actinomyces 
there  may  occur  forms  which  under  certain  conditions  such  as 
wound  infection,  produce  diseases  (chronic  suppurations). 

Some  varieties  of  bacteria  classified  by  Lohnis  as  lacto-bacilli, 
as  for  instance  a  microbe  isolated  by  Chatter jee  from  "Dadhi," 
(Indian  sour  milk)  Streptothrix  dadhi  and  several  bacteria  which 
were  found  in  Mazun,  Yoghurt  and  in  the  Montenegrin  "Grusa- 
vina"  and  "Kysla  varenika,"  appear  from  their  morphological 
properties,  to  belong  to  the  streptothrix  (actinomyces). 

Finally  it  will  be  advisable  to  discuss  the  higher  fungi,  yeasts 
and  moulds  which  occur  in  milk.  They  cause  a  slight  alcoholic  fer- 
mentation of  the  milk;  not  all  varieties  however  attack  the  milk 
sugar,  although  a  great  number  of  the  most  varied  fungi  and 
yeast  are  found  in  milk,  for  instance  penicilia,  mucors,  aspergilli. 

By  far  the  most  frequent  fungus  in  milk  is  the  Oidium  lactis, 
tinder  which  name  are  collected  all  mycelial  forms,  whose  radiating 
mycelia  carry  hyphae,  that  break  up  into  small,  rectangular,  cylin- 
drical members,  the  so-called  oidia,  which  in  proper  media  again 
grow  out  into  a  mycelium.  The  growth  of  the  oidium  varieties 
gives  the  surface  of  the  cream  layer  a  yellowish-white,  velvety,  fre- 
quently wrinkled  appearance,  which  later  may  take  up  a  glassy 
transparent  appearance. 

Oidium  lactis  causes  fermentation  in  sugar-containing  media, 
and  develops  carbonic  acid  and  a  slight  amount  of  alcohol.  A 
pleasant  aroma  results  from  cultures  in  dextrose  but  in  the  split- 
ting up  of  saccharose,  lactose  and  maltose,  an  intensive  cheesy 
odor  develops.  Besides  sugar,  proteids  if  present  are  split  up. 
Therefore  in  the  zones  of  growth  of  the  oidium  varieties  a  pepton- 
ization  is  manifested  in  the  milk.  Lactic  acid  is  also  produced  and 
later  again  disappears. 

Besides  the  oidia  there  may  also  be  found  the  closely  related 


Buttermilk. 


moniliar  varieties  wliicli  at  times  grow  like  the  oidia  with  a  typical 
mycelium,  at  other  times  it  is  a  sporulating  fungus  (Mon.  varia- 
bilis;  candicans,  etc.) ;  also  varieties  of  mycoderma,  which  always 
multiply  in  a  longitudinal  direction,  by  the  protrusion  of  daughter 
cells  which  continuously  bud  out  new  daughter  cells  and  these  con- 
tinue to  grow  in  the  already  established  direction. 

In  the  preparation  of  certain  fermented  forms  of  milk  which 
are  frequently  desired  in  certain  sour  milk  preparations,  the  sporu- 
lating fungi  which  multiply  in  all  directions  of  space  through 
sporulations  are  of  importance. 

Through  their  activity,  that  is  through  the  formed  enzymes, 
the  milk  sugar  is  split  up  into  dextrose  and  D-galactose,  and  ulti- 
mately the  dextrose  is  split  up  into  alcohol  and  carbonic  acid.  Milk 
may  contain  saccharomyces  varieties,  which  form  endospores  and 
torula  varieties,  whose  daughter  cells  no  longer  separate  in  all 
directions  but  arranging  themselves  into  rows  form  mostly  spheri- 
cal shaped  or  sausage-shaped  buds,  and  have  no  endospores. 

Milk  Preparations,  Buttermilk,  Etc.,  Produced  By  Special 

Fermentation. 

Many  varieties  of  foreign  buttermilk  or  sour  milk  have  recent- 
ly become  known  in  this  country.  Especial  dietetic  value  is  attri- 
buted to  them ;  as  to  whether  they  possess  advantages  over  our  own 
buttermilk  or  not  is  not  yet  known.  The  author  believes  that  our 
native  buttermilk  possesses  the  same  advantages  provided  it  is 
prepared  with  the  same  care  as  the  buttermilk  known  as  Yoghurt, 
Mazun,  Leben-raib,  Gioddu  (Sardinia),  etc.,  besides  many  of  the 
foreign  milk  preparations  which  are  marketed  under  various  names 
frequently  contain  nothing  more  than  native  varieties  of  our  lactic 
acid  streptococci  and  certain  cheese  bacteria. 

Yoghurt  is  the  buttermilk  of  Bulgaria.  It  is  prepared  by 
adding  to  the  milk  the  ferment  maya  after  the  milk  has  been  boiled 
down  to  half  of  its  volume,  and  cooled  to  about  50  deg.  C.  The  mass 
is  then  kept  at  40-50  deg.  and  after  10-14  hours  the  Yoghurt  is 
finished.  The  necessary  fermentation  temperature  is  obtained 
through  cooking  boxes,  or  covering  the  hot  vessels  with  non-con- 
ducting material  (woolens).  Weigmann  in  his  "Mycology  of 
Milk"  quotes  the  verbal  information  of  KostoiT  from  which  it  may 
be  seen  that  the  concentration  of  the  boiled  milk  is  not  always  car- 
ried out  in  Bulgaria,  but  a  ferment  (Maya,  in  Bulgarian  Podkwas- 
sa)  is  stirred  up  with  a  small  amount  of  boiled  milk,  which  is  added 
to  the  milk  and  kept  at  45-48  deg.  C.  If  a  sufficient  amount  of  fer- 
ment is  added  the  Yoghurt  is  finished  in  from  3%-4  hours.  It  is 
cooled  for  1-2  hours,  and  may  then  be  consumed. 

According  to  information  obtained  by  the  author  there  is  an- 
other method  of  preparation  in  Bulgaria  which  is  carried  out  by 
the  dairymen,  and  produces  a  primary  Yoghurt.  ^  According  to  the 
description  of  Marcoff,  to  whose  kindness  I  am  indebted  for  this 


172  Milk   Preparations. 


information,  the  dairymen  take  a  widely  grown  herb  (name  was 
unknown  to  Marcoff),  which  they  crush  up  in  small  linen  sacks.  A 
small  quantity  of  the  juice  is  then  squeezed  out  and  added  to  the 
raw  milk,  whereupon  without  further  treatment  the  coagulation  of 
the  milk  takes  place  within  a  few  hours.  From  this  preparation 
the  Yoghurt  then  may  be  prepared. 

According  to  this  description  the  primary  juice  action  may 
be  attributed  to  a  vegetable  rennet.  With  the  plant  juice  other 
bacteria  also  enter  into  the  milk,  the  product  of  which  is  represent- 
ed by  their  elective  cultivation. 

As  effective  bacteria  in  the  production  of  Bulgarian  butter- 
milk are  considered:  1.  A  lactic  acid  long  rod,  which  belongs  to 
the  acidophilic  bacilli  of  the  intestinal  tract :  the  Bacillus  bulgari- 
cus.  This  is  the  aroma  producer  of  Yoghurt.  The  Yoghurt  also 
contains  streptococci  of  lactic  acid;  yeasts  are  not  desirable  (see 
Table  IV). 

The  same  conditions  exist  in  the  Armenian  Mazun,  a  very 
aromatic  preparation  of  buttermilk,  which  is  prepared  from  boiled 
cow  milk,  buffalo,  sheep  or  goat  milk.  Diiggeli  demonstrated  that 
satisfactory  Mazun  (Tartaric  Katych)  contains  principally  three 
varieties  of  microbes,  a  streptococcus,  a  long  rod-shaped  lactic 
acid  bacterium,  and  yeasts,  the  activity  of  which  produces  the 
aromatic  bodies,  besides  a  slight  amount  of  alcohol  and  carbonic 
acid. 

Leben-raib,  according  to  Bist  and  Khoury  contains  five  micro- 
organisms, among  them  being  two  varieties  of  yeast  and  two  lactic 
acid  producers.  The  buttermilk  is  prepared  in  a  similar  way  to 
Kefir,  by  using  cow,  buffalo  or  goat  milk. 

Kefir  has  been  used  for  a  much  longer  time  and  therefore  is 
more  generally  known.  It  contains  alcohol  and  is  very  rich  in  car- 
bonic acid ;  it  has  a  pleasant,  slightly  acid  odor  and  taste.  It  con- 
tains the  milk  proteins  split  up  to  some  extent  (Hueppe)  in  ad- 
dition to  alcohol  and  carbonic  acid  and  a  slight  amount  of  glycerin, 
succinic  acid,  butyric  acid  and  acetic  acid. 

Kefir  is  best  prepared  from  skimmed  milk,  since  in  full  milk, 
cream  clumps  may  readily  result  and  the  Kefir  thereby  becomes 
rancid,  which  diminishes  the  consuming  value.  According  to  Freu- 
denreich  the  fermentation  is  principally  produced  by  four  varieties 
of  organisms  which  include  yeasts,  two  streptococci  varieties,  and 
one  microbe  described  as  the  Bacillus  caucasicus. 

The  yeasts  are  the  Torula  kefir  and  Saccliaromyces  fragilis, 
both  of  which  ferment  lactose.  Investigations  which  have  been  re- 
cently conducted  by  Kuntze  showed  that  the  bacteria  of  Kefir  con- 
sist of  an  aroma-forming  rod  which  produces  casease  and  alcohol, 
and  a  lactic  acid  long  rod  which  at  first  acidifies  the  milk  and  then 
renders  it  alkaline.  They  are  the  Bacillus  esterificans  Maassen  and 
the  Bacillus  kefir  classified  by  Kuntze  as  belonging  to  the  group  of 
butyric  acid  bacilli  (cited  by  Weigmann).  These  bacilli  inoculated 


Kefir.  173 

into  milk,  together  with  ordinary  lactic  acid  producers,  living  in 
symbiosis  with  yeast,  form  granules  which  grow  to  raspberry  sized 
clumps  and  nodes.  Sponge-like  masses  of  ruffle-like  appearance, 
the  so-called  Kefir  kernels  result,  in  which  are  included  the  neces- 
sary varieties  of  microbes.  In  dried  condition  these  kernels  are  of 
the  size  of  millet  seeds,  but  after  treating  with  warm  water  or  warm 
milk  they  swell  and  proliferate  in  the  milk  up  to  the  size  of  a  fist. 
The  small  young  kernels  are  the  best,  as  the  larger  readily  degen- 
erate, become  slimy  and  crumbling  as  compared  with  the  elastic 
granules  of  more  recent  development.  In  order  that  they  may  again 
produce  good  Kefir  they  must  be  subjected  to  treatment  by 
washing,  drying  in  the  sun,  etc.  The  Kefir  kernels  may  be 
purchased. 

The  origin  of  the  Kefir  kernels,  that  is  the  microbe  colonies 
which  are  clumped  in  the  kernels,  is  not  known,  but  the  primary  de- 
velopment may  have  some  connection  with  the  method  of  ferment- 
ing milk  in  containers  made  out  of  goat  skins. 

If  it  is  desired  to  prepare  Kefir  it  is  necessary  to  first  obtain 
the  kernels  which  may  be  purchased.  The  Kefir  kernels  are 
allowed  to  soak  in  boiled  or  lukewarm  water,  and  then  they  are 
transferred  several  times  (3  to  5  times)  from  one  warm  milk  into 
another,  the  milk  being  poured  off  every  3  or  4  hours. 

The  utilizable  Kefir  kernels  increase  in  size  during  this  time 
through  further  swelling,  and  as  a  result  of  becoming  lighter  in 
weight  through  absorption  of  carbonic  acid  they  rise  to  the  sur- 
face of  the  milk,  whereas  kernels  in  which  one  of  the  varieties  of 
microbes  for  some  reason  or  other  became  destroyed  and  degener- 
ated remain  on  the  bottom  of  the  vessel.  If  the  degenerated  variety 
of  microbes  recover  through  longer  treatment  with  raw  milk,  and 
if  the  proper  relation  of  symbiosis  again  appears,  then  these  ker- 
nels are  satisfactory  for  the  production  of  Kefir.  This  condition  is 
manifested  by  the  kernels  rising  to  the  surface  of  the  milk  after 
some  days. 

If  a  tablespoonful  of  these  kernels  is  added  to  about  one-half 
liter  of  milk  and  this  is  allowed  to  stand  for  from  8  to  12  hours 
at  14  to  18  deg.  C.,  with  frequent  shaking,  then  a  primary  or  mother 
Kefir  is  obtained,  from  which  through  further  fermentation  in 
corked  bottles  the  Kefir  may  be  prepared  ready  for  use. 

The  ''millets  of  the  prophet,"  the  Kefir  kernels,  are  strained 
through  a  sieve,  and  the  homogeneous  fermented  milk  is  filled  into 
bottles,  or  from  the  strained  fluid  a  considerable  quantity  is  poured 
into  a  bottle,  to  which  boiled  milk  cooled  to  about  20  deg.  C.  is 
added.  The  bottle  is  then  closed  and  allowed  to  continue  to  fer- 
ment for  from  24  to  28  hours,  at  from  12-15  deg.  C.  In  this 
process  the  casein  and  serum  separate  but  may  be  readily  homo- 
genized by  shaking.  The  Kefir  is  then  ready  for  consumption, 
and  represents  a  thick,  sour,  aromatic  fluid  of  a  pungent  taste, 
with  a  remarkable  nutritive  value. 

A  similar  product  is  prepared  by  the  nomadic  population  of 


174  Milk   Preparations. 


Southern  Bussia,  Siberia,  and  Central  Asia,  which  represents  a 
milk  wine  made  from  the  milk  of  mares  and  asses,  and  which  is 
known  by  the  name  of  Kumys.  In  the  preparation  of  Kumys, 
alcohol  and  carbonic  acid  fermentations  are  the  principal  processes. 
After  long  fermentation  Kumys  contains  up  to  2  %  of  alcohol  and 
\%  or  more  carbonic  acid. 

Bacteriologically  Kumys  is  of  similar  composition  to  Kefir 
containing  yeasts,  lactic  acid,  streptococci,  and  the  Bacillus  kumys 
(Schipin),  which  is  a  facultative  anaerobic  microbe  which  splits  up 
milk  sugar  with  the  formation  of  lactic  acid  and  alcohol  and 
peptonization  of  the  proteids.  These  act  together  and  form 
after  several  days  a  delicious  drink  of  white  color,  and  creamy  con- 
sistence. Special  varieties  of  milk,  containing  much  sugar,  are 
best  adapted  for  the  preparation  of  Kumys  but  cow's  milk  is  the 
least  desirable. 

Gioddu,  the  buttermilk  of  Sardinia,  is  prepared  from  boiled 
milk  cooled  to  about  35  deg.  C.  To  four  parts  of  milk  one  part  of 
old  Gioddu  is  mixed,  the  Gioddu  being  added  to  cow,  sheep  or  goat 
milk.  The  fermentation  is  produced  by  the  Bacillus  sardous  in 
symbiosis  with  the  Saccharomyces  sardous.  According  to  Grisconi 
the  Bacillus  sardous  belongs  to  the  streptobacilli. 

The  preparation  of  buttermilk  constitutes  an  important  branch 
of  the  utilization  of  milk  in  all  countries.  In  northern  Bavaria 
the  milk  is  usually  set  in  large  earthen  pots  and  allowed  to  undergo 
voluntary  fermentation.  In  southern  Bavaria  and  in  the  Bavarian 
forests  the  "fall  milk"  is  utilized  for  the  preparation  of  the 
"sour  soup."  By  keeping  buttermilk  and  continually  adding  sour 
skimmed  milk  to  it  a  fermenting  product  is  obtained  which  is 
thickened  by  the  removal  of  the  whey  (Herz). 

In  Sweden  and  Norway  a  milk  product  is  known  under  the 
name  of  "thick  milk"  (Tatmjolk),  which  is  produced  by  slime  and 
lactic  acid  producing  bacteria  which  vegetate  on  the  leaves  of  the 
butterwort  (Pinguicula  vulgaris). 

The  leaves  of  this  plant  are  placed  on  the  bottom  of  the  milk 
vessel  and  milk  poured  over  them,  whereupon  the  milk  becomes  so 
thick  in  several  hours  that  it  must  be  cut  with  a  spoon  or  knife  in 
order  to  be  taken  into  the  mouth  (Weigmann).  New  milk  may 
be  inoculated  with  the  residue  of  old  milk. 

The  necessary  preparations  of  bacteria  for  the  making  of 
special  forms  of  popular  buttermilk  may  at  the  present  time 
be  purchased  in  the  market.  In  using  any  of  these  ' '  ferments ' '  the 
directions  for  use  should  be  carefully  followed,  since  at  a  tempera- 
ture either  too  high  or  too  low  an  overproduction  of  undesirable 
bacteria  may  readily  take  place  which  would  make  good  results  im- 
possible. Even  if  the  directions  are  carried  out  most  accurately, 
the  propagation  from  milk  to  milk  may  be  a  failure  since  the  biolog- 
ical properties  of  the  bacteria  are  not  absolutely  constant;  the 
microbes  "grow  wild"  and  their  pleasant  qualities  are  lost,  or  they 
may  change,  assuming  undesirable  properties. 


Table  IV. 


Butyric   acid   bacilli   in   boiled   milk,   kept   for   two   days   at   37°C. 
1X1200. 


n. 


Film  of  Yoghurt.  Bacillus  bulgaricus  and  lactic  acid  streptococci. 
Gram-safranin  stain.  1  X  1200. 


Ernst,  Milk  Hygiene. 


Bitter  Milk. 


Porcelain  vessels  and  bottles  made  from  glass  free  of  lead  are 
most  suitable  for  the  preparation  of  buttermilk,  since  the  butter- 
milk may  extract  lead  from  enameled  earthenware  and  from  pots 
whose  glazing  contains  lead  in  its  composition. 

According  to  Chlopin  0 . 84  mg.  of  lead  was  extracted  from  100 
gm.  lactobacillin-buttermilk ;  in  a  second  portion  (300  gm.  butter- 
milk) which  was  five  days  old,  the  amount  reached  7 . 86  mg.  Briick- 
mann  obtained  similar  results :  300  gm.  of  ordinary  buttermilk  con- 
tained after  four  days  4.2  mg.,  and  after  six  days  5.7  mg.  of  lead, 
when  this  product  had  been  prepared  in  pots  with  lead-containing 
glazing. 

Defects  of  Milk. 

Bacteria  produce  certain  modifications  in  milk  which  partly 
on  account  of  their  frequency  are  designated  as  normal  processes, 
or  again  others  appear  which  are  less  frequently  observed,  occur- 
ring only  under  special  conditions  and  therefore  are  known  as 
milk  defects.  The  modification,  as  has  been  seen,  may  be  even 
desirable,  as  for  instance  in  cream  souring  and  cream  ripening 
for  butter  making,  or  in  the  preparation  of  Kefir,  Yoghurt,  and 
buttermilk,  or  it  may  be  undesirable  and  injurious,  spoiling  the 
milk,  and  having  a  disturbing  influence  on  milk  utilization,  espe- 
cially in  its  use  for  drinking  purposes. 

Among  the  changes  in  milk  there  are  those  which  appear  fre- 
quently, and  others  which  are  very  rare. 

Under  conditions  which  favor  propagation  of  peptonizing 
bacteria  (staphylococci,  sarcina,  anthracoides,  mycoides,  mesen- 
tericus  varieties,  fluorescens,  pyocyaneus,  etc.),  the  milk  attains  a 
bitter  taste. 

For  instance  if  uncooled  milk  is  filled  into  cans  which  are 
immediately  closed  it  " suffocates,"  acquiring  a  strong  stable 
odor  which  may  even  reach  a  putrid  character,  causing  a  solution 
of  the  casein  by  reason  of  which-  the  milk  no  longer  coagulates ;  or 
the  appearance  of  a  bacterial  rennet  produces  a  rennet-like  pre- 
cipitation of  the  casein,  and  the  milk  coagulates  without  turning 
sour.  It  is  "sweet-coagulating."  By  the  action  of  peptonizing 
micrococci,  which  in  part  are  psychrophilic  the  development  of  a 
bitter  taste  may  occur  in  thoroughly  cooled,  and  even  in  excessive- 
ly cooled  milk.  The  bacteria  of  the  colon  group  when  the  condi- 
tions of  their  propagation  are  favorable  may  produce  an  odor  in 
milk  ranging  from  aromatic  to  rancid,  or  some  varieties  of  this 
group  which  have  grown  on  mangels  may  confer  the  odor  of  man- 
gels to  the  milk. 

A  bitter  taste  in  milk  may  also  occur  from  the  feeding  of  foods 
containing  bitter  substances,  thus  for  instance  from  the  feeding 
of  lupins,  vetches,  mangels,  camomile,  beet  leaves,  wood-fern,  raw 
potatoes,  mouldy  or  spoiled  hay,  straw,  etc.  It  may  however  be 
accepted  that  the  development  of  a  bitter  taste  in  milk  usually 


17G  Defects  of  Milk. 


results  from  its  contamination  with  varieties  of  bacteria  vegetating 
on  food  substances,  which  enter  into  the  milk  directly  from  the 
stable  air  or  indirectly  with  the  manure  and  litter.  They  then  con- 
vey to  the  milk  this  altered  taste.  Experiments  to  confirm  these 
views  have  been  undertaken  quite  recently  by  Weigmann  and 
Wolf  (Kiel). 

Defective  flavors  are  frequently  present  in  milk. 

Of  1,000  retentions  made  during  1909  in  Munich,  90.50%  were 
on  account  of  souring,  14.6%  on  account  of  soapy  taste,  18.25% 
rancid,  2.19%  fecal  contamination,  8.76%  oily,  1.46%  bitter, 
2.92%  granular,  2.19%  sweet-coagulating,  and  1.46%  on  account 
of  slimy  conditions. 

Eepresentatives  of  the  colon-aerogenes  group  may  actually  be 
cultivated  until  they  become  aroma  producers  if  they  are  allowed 
to  grow  for  instance  upon  media  made  from  rape  leaves.  If  an 
adaptation  of  these  and  other  bacteria  to  the  ingesta  within  the 
gastro-intestinal  canal  is  admitted,  then  an  acquisition  of  certain 
other  properties,  depending  on  the  consumed  feed,  is  readily 
conceivable. 

Weigmann  and  Ritland  and  Jensen  demonstrated  such  "rape 
bacteria"  in  milk  having  a  rape-leaf  taste;  the  milk  at  the  same 
time  had  a  stale  taste  and  an  odor  of  dish-water.  The  author  ob- 
served a  distinct  phosphorus  taste  in  cases  in  which  the  milk  was 
placed  without  being  cooled  into  unclean  or  poorly  cleaned  covered 
cans. 

Animal  and  fecal  odors  result  when  freshly  drawn  milk  is 
placed  into  covered  cans  without  airing  and  cooling.  In  these 
cases  the  vegetation  of  anaerobic  and  facultative  anaerobic  bacteria 
may  play  a  part,  and  the  temperature  may  have  an  effect  on  the 
bacterial  elective  conditions.  The  milk  attains  a  taste  like  animal 
viscera  if  it  contains  bacteria  of  the  mycoid,  megatherium  or  fluor- 
escens  group. 

Fishy  taste  of  milk  may  result  from  pasturing  cows  on  marshy 
meadows  which  have  been  inundated.  In  these  instances  the  pres- 
ence of  various  other  varieties  of  bacteria  should  be  taken  into 
consideration. 

The  multiplication  of  the  Bacillus  lactis  saponacei  (Weig- 
mann) and  the  Bacillus  sapolacticum  (Eichholz),  produces  a  soapy 
condition  of  the  milk.  The  milk  attains  a  sharp,  rancid,  soap-like 
taste,  and  when  cold  it  reminds  one  of  valerian ;  in  a  warm  state 
it  has  a  sharp,  soapy  odor.  In  shaking  such  milk  a  fine,  vesicular, 
persistent,  tenacious  foam  results.  The  change  appears  in  thor- 
oughly cooled  and  excessively  cooled  milk,  and  in  the  cold  season 
of  the  year  and  in  cold  rainy  summers  the  bacteria  are  psychro- 
philic,  originating  from  the  feed  and  straw. 

The  Bacillus  lacticus  saponacei  grows  well  at  room  tempera- 
ture, liquefies  gelatin,  and  produces  a  slight  yellowish  shimmering 
coloring  matter;  the  growth  is  aerobic.  The  Bacterium  sapolacti- 


Blue  Milk.  177 


cum  grows  similarly.  It  is  not  supposed  to  liquefy  gelatin.  The 
nutritive  media  become  fluorescent. 

The  propagation  of  butyric  acid  bacteria  causes  rancidity  of 
milk,  as  does  likewise  the  multiplication  of  bacteria  which  spilt  up 
fats,  for  instance  the  Bacterium  lipolyticum. 

The  appearance  of  the  milk  defects  here  mentioned  may 
sometimes  be  confined  to  the  product  of  a  single  individual  in  the 
stable.  The  milk  of  one  or  of  several  co\vs  may  manifest  these 
defects  which  may  be  retained  persistently  in  spite  of  changing 
the  feed  and  disinfecting  the  stable. 

Weigmann  mentions  a  case  in  which,  with  uniform  feeding  and  care  of  the  animals, 
the  milk  of  only  one  cow  developed  a  fishy  odor,  and  to  such  a  marked  extent  that  the 
milk  of  the  entire  herd  became  fishy  (possibly  the  udder  of  this  cow  was  diseased). 

The  same  author  mentions  another  case  which  occurred  on  an  estate  in  northern 
Germany.  In  that  instance  the  milk  of  the  Montavania  cows  in  the  stable  was  constantly 
rancid,  whereas  the  milk  of  the  Holstein  cows  was  faultless,  although  the  animals  were 
all  kept  under  the  same  conditions.  The  Bacillus  lipolyticum  was  found  to  be  the  dis- 
turbing bacterium.  It  is  noteworthy  that  the  milk  of  the  Montavania  cows  was  frequently 
bloody  at  the  same  time.  Therefore  it  is  possible  that  the  elimination  of  the  aroma 
bacteria  took  place  from  the  affected  udders,  that  is,  the  same  bacterium  was  also  the 
cause  of  the  inflammation  of  the  udder.  However,  it  is  more  likely  that  through  the 
secretion  of  the  affected  udders  conditions  were  established  in  the  milk  from  the  Mon- 
tavania animals  which  favored  the  propagation  of  the  Bacterium  lipolyticum  in  the 
milk,  or  probably  the  bacteria  were  present  in  the  milk  cisterns  of  these  cows  as  harmless 
saprophytes,  and  the  blood  content  of  the  milk  may  be  attributed  to  some  affection  of 
the  udder  (yellow  garget),  which  had  no  connection  with  the  cause  of  the  rancid  milk. 

It  has  also  been  proved  that  other  changes  in  milk  may  per- 
sistently occur  in  the  secretion  of  certain  individuals  so  that  it 
appears  as  if  the  causative  agents  of  the  changes  in  the  milk  may 
at  times  exist  as  saprophytes  in  the  cistern  (Schultze),  or  that 
they  have  at  least  multiplied  in  the  excretory  duct  of  the  cistern. 

Thus  Schultze  proved  that  in  the  appearance  of  "blue  milk" 
the  defect  can  only  be  removed  by  a  thorough  cleaning  of  the  sta- 
ble, animals,  milk  vessels,  and  all  creamery  utensils,  and  the  milk 
cisterns  of  the  animals  must  also  be  treated  by  antiseptic  infusions 
of  the  udder. 

The  "blue  milk"  is  produced  by  the  Bacillus  cyanogenes,  a  Gram-negative,  aerobic, 
actively  motile,  unipolar,  flagellated  bacillus,  with  rounded  ends,  about  0.4/ci  thick  and 
2.4/i  long.  It  is  also  known  as  the  Bacterium  syncyaneum  Hueppe  (Heim).  Growing 
in  sour  milk  the  bacillus  produces  sky-blue  to  indigo-blue  spots  which  gradually  become 
confluent.  The  bacillus  attacks  the  casein,  and  produces  alkali  besides  a  coloring 
substance,  the  triphenylrosanilin  (Erdmann),  which,  depending  on  the  reaction  of  the 
nutritive  media,  appears  greenish  or  pale  blue,  violet  or  indigo-blue,  or  blackish-brown. 
The  Bacillus  cyanogenes  in  itself  is  colorless. 

The  coloring  is  less  typical  in  sterile  milk;  a  dirty  bluish-gray  discoloration  with 
a  reddish  hue  of  the  cream  occurs,  the  color  gradually  diminishing  in  the  deeper  parts. 
Indigo-blue  spots  develop  only  in  sour  milk  (Heim). 

The  changes  which  occur  in  milk  appear  to  be  especially  fre- 
quent in  certain  localities ;  in  others  they  are  more  rare  and  appear 
to  have  a  connection  with  the  properties  of  the  soil.  Pastures  rich . 
in  clover  are  supposed  to  favor  the  appearance  of  the  defects  while 
in  woodland  pastures  they  have  not  been  observed,  or  at  least  only 
exceptionally.  This  would  explain  why  the  defects  occur  in  cer- 

12 


178  Defects  of  Milk. 


tain  periods  during  the  feeding  of  the  incriminated  feeds,  or  while 
the  cows  are  feeding  in  certain  pastures.  According  to  observa- 
tions they  are  observed  more  frequently  in  the  fall,  and  during 
wet,  foggy  weather  than  during  other  periods. 

These  defects  persist  tenaciously  in  creameries  and  dairies 
and  can  only  be  eradicated  after  a  thorough  determination  of  their 
origin.  Disinfection  of  the  milk  room  and  utensils  with  milk  of 
lime  and  hot  soda  solution,  and  extending  this  disinfection  to  the 
stable  in  association  with  cleaning  of  the  animal  and  possibly  an- 
tiseptic infusions  of  the  milk  cisterns  may  yield  the  desired  results. 

Another  organism  causing  "blue  milk"  is  the  Bacterium  cyan- 
eofliiorescens  (Zangemeister).  It  is  actively  motile,  bipolar,  flag- 
ellated, grows  on  gelatin  in  the  form  of  whitish  colonies  with  in- 
dented borders  and  produces  a  fluorescent  coloring  matter  in  the 
nutritive  media.  The  culture  has  an  odor  of  trimethylamin  and 
putrid  fish.  The  bacteria  produce  dark  blue  spots  in  milk  which 
change  to  a  sky-blue  color  after  coagulation  of  the  milk.  Other 
blue  bacteria  are  those  which  occur  on  hay  dust,  in  water,  and  in 
sewage  in  the  vicinity  of  cheese  factories,  in  ditch-water,  and  also 
the  bacteria  cultivated  by  Voges,  Claessen,  and  Beijerinck  which 
have  been  described  under  the  names  of  B.  cceruleum,  B.  indigan- 
aceum,  B.  cyaneofuscum. 

According  to  the  observation  of  Weigmann  and  the  descrip- 
tion of  Hallier  certain  hyphomycetes  may  also  possess  the  faculty 
of  producing  a  blue  coloration;  this  is  accomplished  by  the  ac- 
tion of  the  blue  coloring  matter  which  they  harbor. 

In  the  zone  of  the  milk  supply  of  Munich  ordinary  milk  de- 
fects occur  very  rarely;  the  author  observed  them  in  only  one 
dairy,  and  was  able  to  trace  the  trouble  to  a  certain  farm.  An- 
other defect  of  milk  occurs  much  more  frequently  in  the  vicinity 
of  Munich,  the  cause  of  which,  according  to  the  author,  has  not 
yet  been  described.  It  concerns  the  production  of  brownish  milk. 

The  bacterium  of  brown  milk  appears  to  be  closely  related  in  all  its  characteristics 
to  the  producer  of  blue  milk;  it  is  2.4/x.  long,  0.5/u,  broad,  unipolar,  flagellated,  actively 
motile,  Gram-positive  and  remarkably  resistant  to  drying.  In  gelatin  it  grows  especially 
well  aerobically  as  a  fine,  iridescent  deposit,  which  later  becomes  somewhat  thicker, 
turning  to  a  chestnut  brown  color.  The  oxygen  zone  of  the  lactose  gelatin  retains  a 
saturated  brown  to  deep  brownish  red  discoloration,  the  nutritive  media  becoming  alkaline 
to  litmus. 

A  culture  of  the  brown  milk  organism  may  be  readily  produced  in  milk  by  rubbing 
traces  of  the  culture  of  milk  having  such  a  defect  upon  the  bottom  of  a  large  Petri-dish, 
and  pouring  over  it  fresh  (not  sour)  milk.  In  most  instances  after  15  to  20  hours 
ocher-colored"  to  sepia-brown  spots  develop  in  the  cream  layer,  which  enlarge  and 
coalesce,  conveying  to  the  milk  a  milk  and  coffee-like  appearance.  After  coagulation 
the  superficial  layer  of  milk  again  liquefies ;  whether  this  is  brought  on  by  the  bacteria 
of  brown  milk  alone  or  by  peptonizing  bacteria  which  multiply  especially  well  when 
mixed  with  the  bacteria  of  brown  milk,  which  render  the  media  alkaline,  has  not  yet 
been  established.  The  skimmed  milk  is  not  discolored  by  the  Bacillus  fuscogenes.  The 
brownish  color  gradually  diminishes  from  the  surface  down  and  at  a  depth  of  5  mm. 
it  disappears. 

If  the  milk  is  allowed  to  sour  the  appearance  of  gray,  orange- 
red,  red,  yellow,  green-fluorescent  and  violet  spots  may  frequently 


Red  Milk. 


be  observed,  which  cause  a  glassy,  transparent  thickening  of  the 
wrinkled  yellowish-white  velvety  layer  of  the  oidium  covering,  or 
they  penetrate  into  the  depth  of  the  jelly-like  layer  of  the  milk. 

Thus  under  certain  conditions  the  Bacillus  violaceus,  Bacter- 
ium janthinum,  Bacillus  lividus,  and  Bacterium  amethystinus,  a 
water  organism,  may  appear  in  violet  spots  (Schroeder,  Zopf, 
Maze,  Fliigge  and  others). 

Greenish-yellow  spots  and  discoloration  of  the  entire  sour 
milk  are  produced  by  the  Bacillus  fluorescens  which  varies  greatly 
in  its  characteristics,  at  times  liquefying  gelatin,  again  only  dis- 
coloring it.  It  is  a  short  rod  with  motility,  but  without  spore 
formation. 

A  red  coloring  matter  is  produced  by  the  Bacillus  erytliro- 
genes  Hueppe,  which  coagulates  milk,  but  liquefies  it  later  through 
peptonization,  coloring  the  whey  red. 

According  to  Gruber  a  flagellated  short  rod,  the  Bacillus  lac- 
torubefaciens  is  supposed  to  produce  a  slimy  condition  of  milk 
with  the  formation  of  a  red  coloring  matter.  Other  bacteria  such 
as  the  Micrococcus  cerasinum  (Keferstein),  the  Sarcina  rosea,  the 
Bacillus  prodigiosus  and  others,  form  red  spots.  Red  varieties 
of  yeasts  have  also  been  found. 

The  author  demonstrated  through  the  examination  of  a  dirty 
and  dry  milk  pail  that  the  layers  of  color  which  adhered  to  dif- 
ferent parts  somewhat  like  red  varnish  consisted  of  blue-red  yeasts 
which  had  grown  on  the  dried  milk  residue.  The  accumulation  of 
color  was  present  in  the  yeast  cells  proper,  which  on  examination 
showed  a  reddish  transparency.  Their  attempted  cultivation  was 
unsuccessful. 

The  discolorations  of  milk  may  vary  from  red,  and  pink,  to 
rust-color  and  orange. 

Yellow  coloration  sometimes  only  of  the  cream,  at  other  times 
of  the  entire  milk  is  caused  by  the  Bacillus  synxantlvus  (Schroter), 
the  Sarcina  lutea,  the  Sarcina  flava,  and  Bacterium  fulvum  and 
others.  Wild  yeasts  and  moulds,  which  have  been  observed  by  the 
author  may  also  cause  a  yellow  coloration  of  sour  milk.  The 
Bacillus  fluorescens,  may  at  times  cause  a  yellowish-green 
discoloration. 

Other  bacteria  again  show  the  action  of  their  vegetation  by 
the  development  of  a  tenacious  slimy  consistency  of  the  milk. 
Strains  and  varieties  of  the  peptonizing  bacteria  in  which  acid  for- 
mation is  dissipated  and  the  peptonizing  action  of  which  retracts 
against  the  properties  of  producing  rennet-like  substances,  may  in 
a  few  hours  cause  a  casein  coagulation,  and  thereby  convey  to  the 
milk  a  granular  consistence.  This  defect  is  relatively  rare,  and  on 
the  contrary  the  milk  may  become  non-coagulable,  slimy  and  bitter. 

More  frequently,  especially  by  keeping  the  milk  in  a  warm 
place,  a  change  of  the  milk  to  a  slimy  consistence  may  be  observed. 
The  action  of  the  slime-forming  bacteria  may  appear  in  two  forms, 


180  Defects  of  Milk. 


and  render  slimy  either  the  entire  milk,  or  the  casein  is  precipitat- 
ed and  only  the  whey  develops  a  strong  tenacious,  stringy 
consistency. 

The  cause  of  the  slimy  condition  may  be  produced  either  by 
a  slimy  change  of  the  sugar,  which  is  accomplished  with  the  form- 
ation of  a  high  molecular  weight  body,  the  galactan  or  the  viscose, 
or  by  the  swelling  of  the  bacterial  capsules  which  form  a  mucin- 
like  substance. 

The  best  known  producer  of  slimy  or  stringy  milk  is  the  Strep- 
tococcus hollandicus,  the  cause  of  the  "long  whey,"  which  is  con- 
sidered by  Weigmann  as  a  degenerated  streptococcus  of  lactic  acid 
fermentation.  If  cultivation  of  the  producer  of  the  "long  whey" 
is  continued  at  35  deg.  C.  it  loses  the  property  of  producing  slime, 
and  changes  into  a  lactic  acid  producer. 

From  various  groups  of  bacteria  the  following  have  been 
proved  to  be  slime  producers:  Bacterium  lactis  longi — a  strep- 
tococcus— in  Swedish  thick  milk  (Troili  Petersson),  Micrococcus 
(streptococcus)  viscosus  (Schmidt-Muhlheim),  Micrococcus  mu- 
cilaginosus  from  slimy  cream  (Ratz),  and  Streptococcus  burri 
from  stringy  whey. 

Slime  is  further  known  to  be  produced  by  the  colon-aerogenes 
group  (Emmerling,  Schardinger),  the  Bacillus  guillebeau,  as  well 
as  the  Bacillus  lactorubefaciens.  Adametz,  Duclaux,  Gruber, 
Ward,  Eckles,  and  Marshall  have  also  isolated  slime  producers 
from  milk,  whey,  food  substances,  straw,  stable  air,  and  spring 
water. 

Other  defects  of  milk  which  are  associated  with  change  of 
consistency  (and  color  changes),  are  produced  by  milk  drawn  from 
affected  udders,  which  subject  has  been  discussed  in  the  section 
on  "Diseases  of  the  Udder." 

Considering  the  living  requirements  of  the  special  varieties  of 
bacteria,  the  defects  of  milk  appear  to  be  especially  frequent  under 
certain  weather  conditions  and  in  certain  periods  of  the  year. 
Thus  the  milk  dealers  of  Munich  complained  of  the  appearance  of 
defects  of  taste,  especially  in  the  cool  and  cold  period  of  the  year, 
and  at  the  time  of  changing  the  animals  from  stable  to  pasture 
feeding  and  vice  versa.  The  cause  may  lie  in  the  fact  that  with  the 
beginning  of  the  dry,  that  is  stable  feeding,  the  microbian  flora  of 
the  intestinal  canal  and  of  the  forage  and  the  stable  air  is  different 
from  that  existing  during  the  period  of  pasture  feeding,  and 
thereby  other  species  of  bacteria,  aroma  producers,  contaminate 
the  milk;  likewise  in  certain  cold  climates  and  in  certain  methods 
of  keeping  milk  the  bacteria,  excepting  the  lactic  acid  producers, 
find  just  the  requirements  which  aid  them  in  their  propagation. 

In  1909,  the  following  defects  of  milk  were  found  among  1,000 
samples  examined  monthly: 


Various  Defects. 


181 


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182  Defects  of  Milk. 


At  the  same  time  it  appears  as  though  the  spoiling  of  milk, 
for  instance  by  souring,  is  less  influenced  by  the  temperature, 
which  of  course  may  be  of  importance,  than  by  the  atmospheric 
pressure.  It  could  hardly  be  attributed  to  an  accident  that,  ex- 
cept at  harvest  time  when  the  milking  is  sometimes  hurriedly  done, 
the  number  of  samples  spoiled  by  souring  were  almost  in  recipro- 
cal relation  to  the  measured  average  value  of  the  atmospheric! 
pressure  for  the  month. 

Likewise  in  several  months  a  certain  parallel  exists  between 
the  occurrence  of  dirty  milk  and  souring,  so  that  the  dirt  is  present 
in  largest  amounts  during  August,  September,  October  and 
November. 

Months  in  which  milk  contains  a  great  deal  of  dirt  appear 
also  to  favor  the  requirements  for  the  development  of  a  putrid 
taste.  (Height  in  June,  August  and  October,  harvest  time.)  Dur- 
ing this  period  the  milk  is  not  aired  and  cooled,  so  it  " suffocates." 
The  cans  are  not  cleaned,  and  all  dairy  work  is  slighted. 

Direct  contamination  with  cow  manure  appears  to  be  of  less  importance  in  the 
development  of  an  animal  flavor,  than  pollution  with  bacteria  from  the  skin  of  the 
cow,  which  may  contaminate  the  animal  while  in  pasture.  These  views  are  strongly 
supported  by  the  experiments  of  Wolf  and  Weigmann,  who  proved  the  identity  of  the 
bacterial  flora  of  the  defective  milk  with  the  bacteria  which  were  cultivated  from  the 
pasture  plants,  and  by  the  experiments  in  which  the  authors  succeeded  in  reproducing 
artificially  these  defects  by  using  special  bacteria. 

This  view  is  also  supported  by  the  observations  of  the  author.  A  milk  dealer 
complained  about  the  bad  taste  of  milk  in  a  certain  delivery.  It  was  noticed  that  only 
the  evening  milk  of  the  farm,  and  not  the  morning  milk  possessed  the  defect.  Before 
the  evening  milking  the  animals  were  kept  in  a  pasture  during  the  day.  It  was  remarked 
from  the  beginning  that  the  morning  milk  did  not  have  the  taste,  which  was  the  more 
suprising  since  the  animals  by  standing  in  the  stable  during  the  night  must  have  affected 
the  purity  of  the  stable  air.  Nevertheless  the  evening  milk  which  was  obtained  in  the 
stable  after  a  sufficient  airing  and  cleaning,  possessed  the  objectionable  taste.  Of  course 
the  time  could  have  played  a  part  since  both  the  morning  and  evening  milk  were  delivered 
at  the  same  time,  the  evening  milk  being  allowed  to  stand  all  nisrht  at  a  temperature  of 
12  deg.  C.  The  milk  was  kept  in  a  milk  room  next  to  the  stable. 

The  conditions,  however,  were  not  changed  by  removing  the  milk  immediately  after 
milking,  to  a  well-ventilated  room,  cooled  by  ice. 

The  passing  of  the  odoriferous  substances  into  the  milk  directly  from  the  food 
could  be  excluded  since  the  substances  could  then  have  been  demonstrated  in  the  morning 
milk  as  well,  and  therefore  the  only  explanation  which  remained  was  that  while  lying 
down  the  abdomens  of  the  animals  became  contaminated  with  the  bacteria  of  pasture 
plants  (meadow  grass  and  clover).  These  bacteria  contaminated  the  evening  milk  during 
milking  in  the  stable,  whereas  the  morning  milk  was  principally  contaminated  with 
bacteria  from  the  bedding.  All  other  factors  could  be  given  about  equal  consideration. 
That  the  age  of  the  milk  did  not  play  a  part  was  proven  by  the  fact  that  the  morning  milk 
in  spite  of  longer  keeping  during  both  cold  and  warm  weather  in  exposed  or  covered 
vessels,  had  never  been  affected  by  the  disagreeable  taste. 

It  is  almost  impossible  at  the  present  time  to  establish  definite 
relations  between  defects  in  milk  and  contamination  of  milk  with 
bacteria,  since  the  propagation  of  the  bacteria  causing  the  defects 
may  be  influenced  by  the  most  varied  factors. 

It  should  be  especially  emphasized  that  bacteria  of  one  and 
the  same  species  may  under  certain  conditions  produce  different 
defects  in  milk,  depending  on  the  accompanying  conditions,  as  for 
instance  whether  they  are  associated  with  one  or  several  othei' 
species  of  bacteria. 


Coagulation  Types. 


According  to  Wolff  and  Weigmann  the  Bacterium  fluorescens 
possesses  the  characteristic  of  producing  by  itself  an  ester-like 
odor,  while  together  with  the  Bacterium  mycoides  and  the  Strep- 
tococcus lacticus  it  produces  a  disagreeable  aroma,  and  finally 
with  the  Bacterium  megatherium,  B.  mycoides,  and  lactic  acid 
bacilli  it  produces  a  cheesy  odor.  This  of  course  renders  the  study 
of  milk  defects  difficult,  since  a  bacterium  cultivated  in  pure  culture 
may  show  an  entirey  different  action  than  when  present  in  milk  in 
a  mixed  culture,  and  mixed  culture  experiments  with  the  entire 
flora  would  become  necessary. 

Types  of  Coagulation. 

The  decomposition  and  fermentation  microorganisms,  which 
develop  in  milk,  are  utilized  in  the  examination  of  milk  that  is  in- 
tended for  the  manufacture  of  cheese.  A  fermentation  test  is 
made  from  each  delivery  of  milk,  and  after  a  certain  time  each 
sample  is  tested  for  odor,  taste,  and  in  regard  to  its  appearance 
and  visible  changes. 

According  to  Jensen  the  fermentation  may  be  distinguished  as : 

1.  A  fluid  type, 

2.  A  jelly  type, 

3.  A  gaseous  type, 

4.  A  whey  type, 

5.  A  cheesy  type. 

It  should  be  emphasized  that  milk  samples  rich  in  bacteria 
usually  produce  a  good  jellylike  type,  whereas  in  milk  samples 
containing  few  bacteria,  whey  fermentation  frequently  occurs. 

The  jelly  type  results  in  the  profuse  presence  of  lactic  acid 
formers,  which  distend  and  tear  the  coagulum  by  the  action  of 
aerogenes  varieties  and  cheese  bacteria,  whose  gas  production  fre- 
quently forces  the  coagulum  upwards.  The  milk  becomes  whey 
when  true  saccharomyces  varieties  form  gas  at  the  moment  of 
coagulation.  At  the  same  time  sub-types  may  be  distinguished, 
such  as  porous,  granular  and  flaky.  The  cheesy  fermentation 
type  develops  in  the  presence  of  an  increased  number  of  rennet- 
producing  bacteria. 

These  fermentation  tests  of  milk  are  important  to  ascertain  if 
it  is  in  satisfactory  condition  for  cheese  production.  For  the  de- 
termination of  its  fitness  for  drinking  purposes,  however,  these 
tests  are  of  little  importance,  since  the  questions  relative  to  the 
value  which  these  bacteria  possess  in  the  nutrition  of  man,  have 
never  been  satisfactorily  answered. 

Bacterial  Reductase,  Bacterial  Catalase  and  Lactic  Acid 

Production. 

Among  the  characteristics  of  milk  bacteria,  which  are  of 
especial  interest  are  those  which  are  utilized  in  the  examination 
of  milk,  and  which  may  have  a  disturbing  effect  in  experiments 


184  Reduetase,  Catalase,  Etc. 


conducted  for  the  demonstration  of  original  ferments  because  of 
the  reactions  which  they  cause.  One  characteristic  is  the  reduc- 
ing property  of  some  bacteria  and  their  ability  to  split  up  H202 
into  water  and  molecular  oxygen,  corresponding  to  the  action  of 
catalase. 

The  reducing  action  of  bacteria  as  indicated  by  the  presence  of  reductase,  has 
been  observed  for  a  long  time.  Helmholtz  in  1843  proved  that  putrefactive  changes 
which  could  not  be  demonstrated  by  changes  of  odor  could  be  proved  by  discoloration 
of  litmus  coloring  matter.  Subsequently  this  reducing  action  was  confirmed  by  many 
authors  to  be  the  property  of  various  anaerobic  and  aerobic  organisms.  Thus  according 
to  Gayon  and  Dupetit  the  anaerobes  are  capable  of  forming  ammonia  from  nitrates, 
while  the  Bacillus  prodigiosus,  B.  anthracis,  Spir.  finkler  and  Staphylococcus  citreus 
form  nitrites  out  of  nitrates.  Others  again  reduce  sulphur  to  H2S  (through  "Hydro- 
genase"). 

As  an  agent  for  demonstrating  the  reductase  processes  some  authors,  for  instance 
Spina,  Cahen,  and  Wolff,  use  coloring  substances  which  change  into  leuco-eompounds, 
as  a  result  of  the  reduction,  but  from  renewed  contact  with  the  air  they  become  re- 
oxydized,  as  for  instance  tincture  of  litmus,  thionin,  methylene  blue,  indigo  blue,  neutral 
red,  etc.  Others  again  use  metallic  salts  to  render  the  reduction  directly  visible  (Scheur- 
len  and  Klett,  Gosio),  for  instance  selenite  and  tellurite,  whose  sodium  and  potassium 
compounds  confer  upon  the  colonies  a  brick-red  or  grayish-black  tinge,  by  the  reduction 
or  indirectly,  the  transpiring  reductive  action  is  shown  through  secondary  reactions,  for 
instance  the  formation  of  nitrites  from  nitrates,  through  the  addition  of  iodine  starch 
paste  which  becomes  decolorized  by  the  nitric  acid. 

Methylene  blue  is  used  at  the  present  time  most  extensively 
for  the  reductase  test;  that  is,  the  solution  recommended  by 
Schardinger  consisting  of  5  parts  of  concentrated  alcoholic  methy- 
lene blue  solution  to  195  parts  of  water  is  best  adapted  for  the 
examination  of  milk. 

The  reducing  qualities  of  various  bacteria  towards  methylene 
blue  vary.  Thus  Jensen  established  the  reduction  qualities  of  a 
series  of  milk  bacteria,  and  proved  that  varieties  of  colon,  staphy- 
lococci,  sarcina,  and  mould  fungi,  reduce  rapidly,  whereas  acid 
streptococci  do  not  decolorize  the  solution. 

The  findings  of  Koning,  who  used  cultures  24  hours  old  in  his  experiments,  were 
the  same.  Arranged  according  to  length  of  time,  reductions  take  place  as  follows: 

Bacillus  fluorescens  nonliquefaciens,  in 8  min. 

Bac.  acidi  lactici  Hueppe,  in 12  min. 

Bac.  prodigiosus,  in   10-15  min. 

Bac.  fluorescens  liquefaciens,  in 13  min. 

Proteus  zopfii,  in 15  min. 

Bac.  coli  communis,  in 17  min. 

Bac.  subtilis,   in    30  min. 

Mesentericus,   in    60  min. 

Milk   bacteria  I,  in 80  min. 

Streptococci  of  lactic  acid,  Oidium  lactis  and   2  stable  atmospheric 

bacteria,  not  in 90  min. 

Schardinger  in  1902  stated  that  suspensions  of  the  Bacillus  acidi  laevolactici 
decolorize  in  3  minutes,  the  Bacillus  gasoformans  in  3  minutes,  the  Bacillus  lactis 
pituitosi  in  30  minutes,  the  Bacillus  coli  in  15  to  20  minutes,  etc. 

The  ability  to  reduce  methylene  blue  has  also  been  found  in  anthrax  and  tubercle 
bacilli. 

In  the  experiments  it  was  proved  that  although  not  all  bacteria  are  capable  of 
reducing  methylene  blue,  the  power  of  reduction  in  some  is  very  strong,  while  in  others 
it  is  diminished  and  in  still  others  it  is  practically  nil. 

Reduction  properties  appear  to  be  characteristic  of  the  living 


Reducing  Properties  of  Milk.  185 


bacterial  cell,  which  do  not  pass  into  the  filtered  fluid  (Schar- 
dinger,  Spina,  Cahen). 

From  the  above  mentioned  facts  it  is  evident  that  milk  which 
contains  numerous  bacteria  has  a  strong  reducing  property. 
Through  the  works  of  Smidt,  Miiller,  and  Schardinger  it  has  been 
proved  that  as  a  rule  the  richer  the  milk  is  in  bacteria  the  earlier 
the  reduction  of  the  aqueous  methylene  blue  solution  at  37  deg. 
will  occur.  Milk  drawn  under  sterile  conditions  fails  to  reduce  the 
methylene  blue  solution  even  after  days  (Rullmann).  Miiller 
proved  that  freshly  drawn  and  cleanly  handled  market  milk  re- 
quires 10, 12  or  more  hours  for  reduction  (mixing  10  parts  to  1  part 
of  methylene  blue  solution),  whereas  fresh  market  milk  during 
cold  weather  requires  6  to  9,  and  in  warm  weather  only  1  to  2  hours 
for  the  decolorization.  At  the  stage  when  bacteria  begin  to  multi- 
ply, which  is  at  the  end  of  the  incubation  period,  the  time  required 
for  reduction  amounts  to  from  1  to  2  hours.  If  sour  milk  or  cow 
manure  was  added  to  fresh  milk  the  time  of  reduction  was 
hastened. 

He  therefore  proved  that  all  factors  which  favorably  influence 
bacterial  growth  hasten  the  reduction. 

In  the  author's  first  investigation  he  found  that  10  c.  c.  of  milk  with  about  44,000 
bacteria  per  c.  c.  failed  to  reduce  one  c.  c.  of  methylene  blue  solution  in  six  hours. 

With  about          200,000  bacteria  reduction  took  place  in 4  to   6      hrs. 

With  about          500,000  bacteria  reduction  took  place  in 3.5  hrs. 

With  about       1,600,000  bacteria  reduction  took  place  in 2      hrs. 

With  about       6,000,000  bacteria  reduction  took  place  in 70     min. 

With  about  350,000,000  bacteria  reduction  took  place  in 50     min. 

With  about  800,000,000  bacteria  reduction  took  place  in 15     min. 

Similar  results  were  obtained  by  Jensen  as  follows: 

With  about  264,000,000  bacteria  reduction  took  place  in 1     min. 

With  about     80,000,000  bacteria  reduction  took  place  in 3   to   5     min. 

With  about     50,000,000  bacteria  reduction  took  place  in 10     min. 

With  about  7,000,000  to  11,000,000  bacteria  reduction  took  place  in  40  to  60  min. 

With  about       3,000,000  bacteria  reduction  took  place  in 2%  hrs. 

With  about       1,600,000  bacteria  reduction  took  place  in 7%  hrs. 

With  about       1,000,000  bacteria  reduction  took  place  in 6%  hrs. 

With  about         126,000  bacteria  reduction  took  place  in 9^  hrs. 

Since  the  degree  of  acidity  increases  with  the  growth  of  bac- 
teria there  exists  a  certain  connection  between  the  degree  of  acidity 
of  the  milk  and  the  rapidity  of  reduction,  and  since  the  degree  of 
acidity  increases  rapidly  after  incubation,  a  rapid  reduction  would 
be  expected  to  follow  a  rapid  increase  in  the  degree  of  acidity. 

This  is  also  proved  by  Jensen 's  experiments.     Milk  which  reduced  in  one  minute 
had  after  12  hours,  at  25  deg.  C.,  a  degree  of  acidity  of  36. 
Milk  which  reduced  in — 

5  min.  after  12  hrs.  at  25  deg.  had  an  acidity  of 19 

8  min.  after  12  hrs.  at  25  deg.  had  an  acidity  of 20 

6  min.  after  12  hrs.  at  25  deg.  had  an  acidity  of 35 

10  min.  after  12  hrs.  at  25  deg.  had  an  acidity  of 22 

8  min.  after  12  hrs.  at  25  deg.  had  an  acidity  of 18 

7  min.  after  12  hrs.  at  25  deg.  had  an  acidity  of 28 

1      hr.  after  12  hrs.  at  25  deg.  had  an  acidity  of 15 

y2  hr.  after  12  hrs.  at  25  deg.  had  an  acidity  of 25.5 

1%  hr.  after  12  hrs.  at  25  deg.  had  an  acidity  of 11.5 


186  Reductase,  Catalase,  Etc. 


2J/4  hr.  after  12  hrs.  at  25  deg  had  an  acidity  of 15 

3%  hr.  after  12  hrs.  at  25  deg.  had  an  acidity  of 9 

6*4  hr.  after  12  hrs.  at  25  deg.  had  an  acidity  of 9 

7      hr.  after  12  hrs.  at  25  deg.  had  an  acidity  of 10.5 

6y2  hr.  after  12  hrs.  at  25  deg.  had  an  acidity  of 8 

7%  hr.  after  12  hrs.  at  25  deg.  had  an  acidity  of 8 

12%  hr.  after  12  hrs.  at  25  deg.  had  an  acidity  of 7 

8y2  hr.  after  12  hrs.  at  25  deg.  had  an  acidity  of 7.5 

The  findings  of  the  author  were  very  much  the  same  as  those  of  Jensen. 
Milk  which  failed  to  reduce  in  20  hours  had  after  24  hours  at  20  deg.,  from  7.4  to 
10  degrees  of  acidity. 

The  following  table  shows  the  results  of  the  technique  em- 
ployed in  testing  milk,  where  the  reduction  number  is  understood 
to  mean  the  number  of  drops  of  methylene  blue  solution  which  in 
a  given  time  was  completely  reduced  by  5  c.  c.  of  milk: 

Degree  of  acidity  After  24  hrs.  Time  required 

at  delivery  at  20  deg.  for  reduction  Reduction  number 

7.0  7.4                                      20  hrs.                                         0 

6.2  8.6                                      20  hrs.                                         0 

6  10                                         20  hrs.                                         0 

6  9  20  hrs.  4 

7  10  20  hrs.  0 
6                                       24                                           4  hrs.  2 

6.4  26.5  8  hrs.  10 

6.5  26  8  hrs.  6 
6.2  24  8  hrs.  8 
6.2  27  8  hrs.  6 
6.8  23  8  hrs.  4 
6  14  8  hrs.  4 
7.8  30  6  hrs.  4 
6.5  28  2  hrs.  2 
7.2  32  Ihr.  2 
6  34  Ihr.  2 
6.2  38  Ihr.  10 

8  40  5  hrs.'  10 
10.5  26.4  0.5  hrs.  10 

6  30  6  hrs.  2 

These  numbers  were  obtained  from  a  great  number  of  sam- 
ples during  work  at  the  milk  control  station,  without  any  selec- 
tion. They  show  that  milk  which  sours  rapidly,  and  is  therefore 
at  the  end  of  the  incubation  period,  also  reduces  rapidly;  there 
exists,  however,  no  absolute  constancy  in  the  parallelism,  neither 
with  the  values  of  acidity  in  milk  after  twelve  to  twenty-four 
hours,  nor  with  the  values  in  samples  of  fresh  milk. 

After  thorough  souring  the  reduction  power  of  the  milk  again 
diminishes  for  a  time.  This  may  be  due  to  the  fact  that  the  acid 
reaction  inhibits  the  reduction  power — as  a  matter  of  fact  the 
rapidity  of  reduction  is  again  considerably  increased  by  the  addi- 
tion of  sodium  carbonate  or  bicarbonate — and  also  because  a  non- 
reducing  organism,  the  acid  streptococcus,  outgrows  the  other 
bacteria. 

The  addition  of  an  alkaline  solution  brings  about  acceleration 
of  the  reaction  only  in  sour  milk,  while  in  milk  with  low  bacterial 
count  the  reaction  is  retarded,  but  this  may  be  overcome  when 
through  acid  formation  neutralization  has  taken  place. 


Bacterial  Catalase. 


Antiseptics,  such  as  boracic  acid,  salicylic  acid  and  formalde- 
hyde, inhibit  or  destroy  the  reduction  power  of  bacteria;  the 
same  result  is  obtained  by  heating,  which  destroys  the  life  of 
the  vegetating  bacterial  cells. 

Milk  which  has  been  heated  for  10  to  30  minutes  at  80  to  100 
deg.  C.  shows  only  the  slightest  reduction  power,  which  increases 
again  only  after  the  recurrence  of  bacterial  multiplication. 

It  should  be  emphasized  that  milk,  in  spite  of  being  spoiled 
to  a  marked  degree,  may  have  a  slow  reducing  power,  as  for 
instance  soapy  milk,  provided  this  condition  is  not  associated  with 
extensive  bacterial  contamination  with  other  species  of  bacteria. 
Although  the  bacillus  of  soapy  milk  reduces  very  rapidly,  soapy 
milk  in  itself  is  only  capable  of  bringing  on  this  reaction  to  a 
very  slight  degree,  which  probably  is  proof  that  defective  flavors 
may  result  even  when  only  a  very  slight  bacterial  growth  has 
taken  place,  although  the  bacterial  action  is  of  tremendous 
importance. 

For  the  completeness  of  this  chapter  it  should  be  mentioned 
that  milk  very  rich  in  bacteria,  which  has  been  sterilized  by  heat, 
reduces  also  the  formalin  methylene  blue  solution  as  a  result  of 
the  original  bodies  in  milk,  a  property  which  has  nothing  to  do 
with  the  Schardinger  reaction. 

The  formalin  methylene  blue  reducing  principle  in  market 
milk  is  also  a  pre-formed  substance,  which  occurs  in  milk  drawn 
under  sterile  conditions  (original  ferments). 

Bacterial  Catalase. 

Similar  to  the  power  possessed  by  body  cells  and  body  juices, 
bacteria  have  the  ability  of  splitting  gaseous  oxygen  from  hydrogen 
peroxide  solutions.  This  property  may  be  observed  in  many  bac- 
teria, but  it  should  be  mentioned  that  not  all  species  of  bacteria 
possess  it,  and  that  certain  bacteria  have  a  specific  power  in  .this 
direction. 

Koning  and  Jensen  made  confirmatory  statements  to  this 
effect,  having  found  that  the  acid  streptococci  of  milk  do  not  split 
H202.  The  author's  experiments  confirm  this  observation.  Jensen 
made  an  especially  interesting  observation,  namely,  that  the  bac- 
terial flora  present  in  milk  during  the  incubation  period  of  souring 
usually  possess  strong  catalytic  properties. 

The  following  data  are  taken  from  a  work  of  Koning,  arranged  according  to  the 

catalase  figures: 

Species  of  Bacteria  Catalase  test  Keductase  test 

B.  prodigiosus    58  15  minutes 

B.  proteus  zopfii   57  15  minutes 

Milk  bacterium   1 55  80  minutes 

B.  fluorescens  liquefaciens 53  13  minutes 

B.  coli  communis 39  17  minutes 

B.  lact.  acid.  Hueppe   '. 32  12  minutes 

Stable  air  bacteria  II 31  90  minutes 

B.  mesentericus    30  60  minutes 

B.  fluorescens  nonliquef.   29  15  minutes 


188  Reduetase,  Catalase,  Etc. 

Stable  air  bacteria  1 28  90  minutes 

B.  subtilis 17  40  minutes 

Milk  bacteria  II 15  90  minutes 

B.  mycoides 11  90  minutes 

Oidium  lactis   11  90  minutes 

Str.  mastitis  longus 0  90  minutes 

From  these  figures  it  may  be  seen  that  frequently  with  a  high 
catalase  number  a  very  rapid  reduction  time  may  be  present. 

Jensen  found  similar  conditions  in  his  investigations;  he, 
however,  expresses  himself  as  believing  that  a  parallelism  of 
both  factors  does  not  prevail.  Arranged  according  to  catalase 
values  expressed  in  figures,  giving  the  number  of  c.  c.  's  of  oxygen 
formed,  the  relation  between  catalase  and  the  time  of  reduction  is 

as  follows :  Catalase  Keductase 

B.  proteus  vulgaris 27  c.  c.  7  minutes 

B.  proteus  zopfii 27  c.  c.  5  minutes 

B.  prodigiosus   27  c.  c.  7  minutes 

Microc  candic 27  c.  e.  4  minutes 

Microc.  A 27  c.  c.  3  minutes 

B.  coli   18  c.  c.  5  minutes 

B.  aerogenes 9  c.  e.  10  minutes 

B.  mycoides    7  c.  c.  12  minutes 

B.  dentrificans   1  c.  c.  10  minutes 

With  other  bacteria,  for  instance,  butyric  acid  bacteria,  there 
appears  to  be  no  relation  between  the  reduction  power  and  the 
development  of  oxygen,  whereas  with  certain  lactic  acid  producers, 
for  instance,  the  streptococci  and  cheese  bacilli,  the  inability  to 
develop  oxygen  coincides  with  the  long  time  required  for  reduction. 

In  unspoiled  milk  during  the  incubation  stage  of  souring  and 
at  the  beginning  of  souring  at  the  end  of  this  incubation  stage,  the 
bacterial  catalase  will  always  have  to  be  considered,  but  in  general 
the  bacterial  action  in  slowly  reducing  milk  is  very  slight.  If  in 
the  latter  instance  high  catalase  values  are  obtained  then  usually 
the  catalase  originally  present  in  the  milk  is  responsible  for  it. 

Koning  further  showed  that  catalase  increases  with  the  age  of  milk,  and  with  a 
rapid  angle  of  incidence.  The  line  of  incidence  in  fresh  milk  is  at  first  only 
slightly  bent,  later  more  or  less  so,  whereas  old  milk  uniformly  shows  a  rising  line. 
Spindler's  recent  experiments  confirm  this  statement.  From  the  investigations  of 
Spindler,  however,  it  may  be  observed  that  during  the  time  when  milk  is  fresh  enough 
for  drinking  purposes  the  fluctuations  are  only  very  slight  and  the  catalase  value 
obtained  is  always  greatly  dependent  on  the  original  catalase  value  of  freshly  drawn 
milk.  Faitelowitz  indicates  that  catalase  multiplies  many  fold  after  keeping  fresh  milk 
at  room  temperature  for  24  to  30  hours. 

Through  heating  to  70  deg.  C.  the  " bacterial  catalase"  is 
destroyed,  or  at  least  the  bacteria  are  attenuated  in  their  action  to 
such  an  extent  that  the  oxygen-splitting  property  becomes  almost 
nil.  Chick  has  already  ascertained  that  this  inactivation  of  the 
bacterial  catalase  may  be  abrogated  in  a  certain  time  by  inoculation 
of  the  heated  milk  with  raw  milk  and  Koning  states  that  old 
pasteurized  milk,  or  milk  freshly  pasteurized  with  insufficient  heat, 
splits  the  H202.  The  catalase  test  is  therefore  recommended  by 
Kniisel  for  the  examination  of  pasteurized  milk  as  to  its  suitability 
for  drinking  purposes. 


Acidity  of  Milk. 


It  is  to  be  regretted  that  the  bacterial  catalase  cannot  be 
separated  from  the  original  catalase,  so  that  it  would  be  possible 
to  draw  definite  conclusions  from  the  catalase  findings  of  market 
milk,  as  to  whether  the  catalase  quantities  which  are  demonstrated 
were  present  in  the  freshly  drawn  milk  or  whether  they  have  been 
subsequently  formed  by  bacterial  growth.  Wolf  claims  that  milk 
which  reduces  slowly  and  shows  a  strong  catalytic  property  by 
the  formation  of  large  quantities  of  oxygen  should  be  suspected 
of  containing  secretions  from  animals  with  affected  udders.  It 
would  be  impossible  to  draw  conclusions  based  on  this  statement 
in  those  cases  where  rapid  reduction  occurs  coincidently  with 
strong  catalytic  action. 

Degree  of  Acidity. 

In  discussing  the  original  properties  of  milk  it  was  mentioned 
that  casein,  acid  salts  of  milk,  carbonic  acid,  etc.,  give  to  milk  an 
acid  reaction  to  phenolphthalein. 

Even  immediately  after  milking,  in  order  to  produce  neutral- 
ization of  the  milk  against  phenolphthalein,  several  c.  c.  of  sodium 
hydrate  are  required.  The  number  of  cubic  centimeters  of  a 
normal  Na  OH  dilution  which  are  needed  to  neutralize  a  certain 
quantity  of  milk  are  known  as  degrees  of  acidity.  The  number 
obtained  varies,  depending  on  the  method  and  dilution  employed. 

Thus  Soxhlet-Henkel,  for  instance,  employed  100  c.  c.  of  milk 
and  14  normal  Na  OH  and  obtained  an  average  value  of  about 
6  to  7  degrees  of  acidity. 

Jensen,  who  works  with  TO  normal  Na  OH,  uses  on  an 
average  18  to  19  c.  c. 

Thorner  dilutes  10  c.  c.  of  milk  with  30  c.  c.  of  water  and 
titrates  with  TO  normal  Na  OH. 

The  degrees  of  acidity,  as  determined  by  Domic,  are  higher 
than  those  of  Soxhlet-Henkel :  He  uses  10  c.  c.  of  milk  and  alkali 
which  contains  4.445  gm.  Na  OH  to  1000  H20.  tV  c.  c.  of  alkali, 
according  to  Domic,  is  equal  to  a  degree  of  acidity. 

Schrott-Fichtl  and  Domic  suggested  as  an  advantage  the  drop- 
ping of  the  "scale  of  degree  of  acidity"  and  employing  an  alkali, 
1  c.  c.  of  which  would  correspond  to  0.01  gm.  of  lactic  acid,  or  to 
figure  the  degree  of  acidity  on  the  basis  of  lactic  acid.  Then 
1  c.  c.  of  TO  alkali  would  correspond  to  0.009  gm.  of  lactic  acid 
and  1  c.  c.  of  *4  normal  Na  OH=22.5  gm. 

Of  course,  it  should  be  remembered  that  the  neutralization 
of  the  alkali  does  not  correspond  entirely  to  the  amount  of  lactic 
acid  present  but  depends  also  on  other  factors,  for  instance,  on 
the  proportion  of  acid  phosphates,  carbonic  acid  and  casein. 

Only  the  increase  in  acidity  which  is  obtained  by  a  compara- 
tive testing  of  fresh  milk  and  an  older  sample  of  the  same  milk, 
should  therefore  be  considered  as  lactic  acid,  since  Henkel  proved 
that  free  lactic  acid  is  not  present  in  freshly  drawn  milk. 


190  Reductase,  Catalase,    Etc. 

The  degree  of  acidity  of  milk  depends  on  the  lactation  period. 
Colostrum,  milk  of  animals  with  affected  udders,  and  milk  from 
freshly  milking  cows  have  an  abnormally  high  acidity,  while  milk 
from  animals  in  the  last  stages  of  lactation,  and  sometimes  milk 
from  affected  udders,  may  be  lower  than  normal. 

Besides  these  factors  the  degree  of  acidity  of  milk  is  also 
influenced  by  the  growth  of  bacteria,  the  species  of  bacteria,  and 
therefore  by  all  factors  which  have  an  influence  on  the  bacterial 
growth,  such  as  cleanliness  in  milking,  cooling,  outside  tempera- 
ture, age  of  the  milk,  etc. 

Plaut,  for  instance,  demonstrated  that  milk  which  has  been  kept — 
At  a  temperature  of  showed  multiplication  of  and  voluntarily  coagulated 

bacteria  after  after 

10  deg.  C.                                    48  to  72  hrs.  100  hrs. 

15  deg.  C.                                    20  to  24  hrs.  63  hrs. 

20  deg.  C.                                    12  to  20  hrs.  48  hrs. 

25  deg.  C.                                               8  hrs.  24  hrs. 

31  deg.  C.                                               7  hrs.  22  hrs. 

37  deg.  C.                                               5  hrs.  12  hrs. 
Koning  has  also  kept  milk  at  various  temperatures  and  titrated  the  degree  of  acidity 
after  varying  periods: 

Kept  at  7  to  9  deg.  C.  Kept  at  22  deg.  C. 

Deg.  of  aciditv  Deg.  of  acidity 
with  l/jo  NaOH 

Milk  after  delivery 13.6  13.6 

After    15   hours 14.6  14.6 

After   29   hours 14.6  20.6 

After   41   hours 16.0  62.6 

After   53    hours , 16.0  71.0 

After   65   hours 16.8 

After    77   hours 17.6 

After   89  hours 18.8  

Since  the  growth  of  various  bacteria  depends  on  the  method 
of  keeping  the  milk,  therefore  the  acid  formation  varies  in  accord- 
ance with  the  same  conditions  during  the  same  time.  Koning's 
experiments  confirm  these  findings : 

Time  of  Milk  in  shallow  vessels  In  tall  cylinders 

delivery  at  22  deg.         at  37  deg.  C.          at  22  deg.         "  at  37  deg.  C. 

Shortly  after  milking.  18.6 

After  24  hours 16.4  18.5  18.8  32.4 

The  degree  of  acidity  depends,  furthermore,  upon  whether 
fresh  milk  is  boiled  or  raw;  in  boiled  milk  it  is  lower  than  in  raw 
milk,  and  it  also  depends  on  the  aeration  of  the  milk. 

Milk  drawn  carefully  into  bottles  25  minutes  after  the  milk- 
ing has  17.4;  after  being  aired  by  pouring  from  a  height  of 
y2  meter,  16.4;  after  repeated  aeration  16.1,  and  after  boiling 
only  16  degrees  of  acidity  (Koning).  The  escape  of  the  volatile 
carbonic  acid  seems  to  play  a  part  in  this. 

Finally,  the  degree  of  acidity  depends  on  the  method  by  which 
it  is  tested.  For  instance,  if  the  milk  is  diluted  with  water  for 
the  purpose  of  titration  (method  of  Thorner,  Pfeifer,  etc.),  then 
through  this  addition  of  water,  a  solution  of  alkaline  calcium 
phosphate  takes  place  and  the  acidity  becomes  less. 


Typhoid  Fever  from  Milk.  i  qi 


Since  the  acidity  varies  immediately  after  milking,  after  lac- 
tation, among  individuals,  and  even  in  milk  from  different  teats, 
and  from  interrupted  milkings,  the  immediate  measuring  of  the 
degree  of  acidity  constitutes  no  proof  of  the  age  of  the  milk.  The 
periodically  continued  titration  of  the  same  sample  may,  however, 
be  a  good  indication  as  to  whether  the  milk  has  passed  the  incu- 
bation phase  and  thereby  afford  an  approximate  indication  of 
the  "age."  By  "age"  is  not  understood  the  difference  in  time 
between  milking  and  examination,  but  a  condition  which  may  ap- 
pear in  milk  sooner  or  later,  depending  on  the  cleanliness  in  its 
preparation  and  handling,  and  on  the  outside  temperature.  This 
condition  is  effectively  determined  by  the  reduction  of  methylene 
blue.  If  the  milk  has  once  passed  the  incubation  time  the  curve 
of  acidity  rapidly  and  progressively  rises,  when  the  milk  is  kept 
subsequently  at  temperatures  at  which  lactic  acid  bacilli  grow  pro- 
lifically  (20  to  37  deg.). 

Koning  made  a  test  of  milk  which  at  delivery  gave  a  degree 
of  acidity  of  15.8  (TV  n  Na  OH  :100), 

And  showed  after  at  10  deg.  22  deg.          37  deg.  C. 

1  day 16.4  28.8  96.0 

2  days  16.7  91.1  92.8 

3  days  17.2  102.4  105.2 

4  days 17.9  96.4  144.0 

5  days   26.2  105.6  184.0 

6  days   39.2  103.2  219.6 

7  days   57.6  102.8  241.6 

8  days   65.2  106.0  261.6 

Since,  however,  the  amount  of  lactic  acid  formation  does  not 
depend  on  the  time  and  temperature  alone,  but  also  on  the  variety 
of  bacteria  growing  in  the  milk,  only  general  conclusions  as  to 
the  aging  of  the  milk  can  be  drawn. 

Subsequent  Contamination  With  Infections  of  Man. 

The  occurrence  of  disease  producing  agents  in  milk  is  of 
interest  from  the  standpoint  of  tracing  the  origin  of  disease, 
but  from  a  milk  inspection  standpoint  it  is  a  most  thankless  field. 
These  disease  producers  may  originate  from  affected  persons,  or 
from  healthy  bacilli  carriers,  or  they  may  reach  the  milk  through 
infected  material,  as,  for  instance,  infected  water  used  in  washing 
utensils,  or  as  an  adulterant,  or  in  the  treatment  and  preparation 
of  milk  products. 

That  milk  may  become  a  transmitter  of  disease  has  been  posi- 
tively proven. 

1.  Typhoid  Fever.  The  causative  agent  may  contaminate 
the  milk  through  infected  water,  through  vessels  which  were 
returned  without  cleaning  from  houses  harboring  persons  affected 
with  typhoid,  through  affected  and  convalescing  patients  who  are 
employed  in  producing  or  in  the  subsequent  handling  of  milk,  and 


192  Infections  of  Man  from  Milk. 


through  attendants  and  other  intermediate  hosts,  especially 
through  bacilli  carriers.  Konradi  positively  demonstrated  typhoid 
bacilli  in  such  milk.  Levy  and  Jakobstal  discovered  true  typhoid 
bacilli  in  an  abscess  of  a  cow  so  that  under  certain  conditions  it 
should  be  considered  possible  for  typhoid  bacilli  to  gain  entrance 
into  the  milk  directly  from  the  udder  of  the  cow. 

2.  Paratyphoid  Fever.    All  that  applies  to  typhoid  bacilli 
holds  equally  true  for  paratyphoid,  and  to  other  bacteria  of  that 
type,  for  instance  the  Bacillus  enteritidis  and  the  Bacillus  paracoli. 

In  these  affections  especial  attention  should  be  directed  to 
the  animals  which  are  affected  with  intestinal  inflammations, 
purulent  metritis,  and  acute,  severe  inflammations  of  the  udder, 
and  also  to  stables  in  which  white  scours  of  calves  and  calf-ill 
occur  frequently. 

The  possibility  of  the  transmission  of  scours  to  man  has  been 
indicated  by  Lenz,  Jehle  and  Charleton.  Up  to  the  present  time, 
however,  its  certain  transmissibility  through  milk  has  not  been 
satisfactorily  demonstrated. 

3.  Cholera. 

4.  Diphtheria. 

5.  Tuberculosis.    Babinowitsch  demonstrated  tubercle  bacilli 
of  human  type  in  milk. 

6.  Scarlet  Fever. 

The  sanitary  police  or  the  authorities  in  charge  of  milk  con- 
trol in  all  cases  in  which  a  suspicion  prevails  that  such  diseases 
have  been  transmitted  through  milk  can  provide  that  the  possi- 
bility of  the  continued  spread  of  such  infections  should  be  pre- 
vented. The  sanitary  police  authorities  should  continuously  im- 
press upon  all  persons  interested  in  the  production  of  milk,  and 
in  the  dairy  industry,  that  there  are  always  possibilities  of  the 
transmission  of  disease ;  and  the  attendant  physicians  should  cau- 
tion the  patients  and  their  families  as  to  the  danger  of  allowing 
it  to  spread  further,  and  any  violations  should  be  dealt  with  to 
the  extent  of  the  law. 

The  health  authorities  of  a  locality  at  every  appearance  of  a 
dangerous  epidemic  should  consider  the  possibility  of  the  develop- 
ment of  the  disease  through  milk  consumption,  and  should  trace 
the  places  from  which  the  affected  persons  and  their  families 
draw  their  milk  supply.  If  from  these  investigations  there  exists 
the  slightest  cause  to  assume  that  the  milk  supply  may  be  the 
original  cause,  the  attending  physicians  should  cause  a  further 
investigation  of  the  matter.  In  the  meantime  the  suspected  milk 
should  be  rendered  harmless  by  pasteurization. 

With  these  remarks  an  intrusion  has  been  made  into  the 
chapter  upon  "the  supervision  of  the  milk  traffic  and  milk  control," 
which  will  be  given  special  consideration. 


Destruction   of  Bacteria  by   Heat.  193 

The  Destruction  of  Bacteria  in  Milk. 

it  is  jur  purpose  to  discuss  briefly  the  destruction  of  bacteria 
in  milk,  which  aims  to  free  the  milk  from  disease-producing  germs 
and  add  to  the  keeping  quality  of  the  milk. 

In  practice  this  is  accomplished  most  frequently  by  heating, 
in  which  the  following  distinctions  are  made : 

1.  Sterilization  of  the  milk; 

2.  Simple  boiling; 

3.  Pasteurization. 

If  it  is  desired  to  judge  the  value  of  these  methods  of  prepa- 
ration, the  question  first  considered  must  be,  what  changes  does 
the  milk  undergo  through  heating?  Milk  is  a  biological  product 
the  properties  of  which  may  be  considerably  influenced  by  cold 
and  heat. 

It  is  generally  known  that  after  heating  milk  retains  a  so- 
called  boiled-milk  taste,  and  that  this  becomes  stronger  the  longer 
the  milk  is  subjected  to  a  temperature  of  from  70  to  100  deg.  C. 

The  method  of  heating  is  important  for  the  appearance  of  the  cooked  taste. 
Open  boiling  even  for  a  short  time  produces  a  marked  change  in  taste  when  compared 
with  heating  in  specially  closed  utensils  or  in  bottles  after  subsequent  cooling. 

The  curdling  of  boiled  milk  is  more  difficult  than  with  raw 
milk;  the  boiled  milk  in  curdling  after  a  long  time  forms  a  loose, 
coagulum  with  less  uniform  consistency.  This  change  is  not  so 
pronounced  with  heating  between  70  to  80  deg.  as  in  boiling  and 
in  heating  to  over  100  deg.  C. 

Depending  on  the  height  of  the  temperature  and  on  the  length 
of  time  the  heat  is  applied,  globulin  (at  75  deg.)  and  albumin  (at 
80  deg.)  are  precipitated.  Proteids  which  are  precipitated  in  milk 
by  heating  to  boiling  temperature  disappear  if  the  boiling  is  con- 
tinued. According  to  Peiper  and  Eichloff  the  intermolecular  at- 
tachments of  the  proteids  become  loosened  by  heating  to  high 
temperatures,  and  leucin,  tyrosin,  ammonia,  sulphureted  hydrogen 
and  phosphorated  hydrogen  are  formed.  If  the  heating  has  been 
conducted  in  poor  earthenware  or  glass  vessels,  especially  new 
ones,  potassium  silicate  will  pass  into  the  milk.  Fynn  noted  the 
absence  of  sulphureted  hydrogen  from  heated  colostral  milk.  The 
reaction  became  apparent  only  on  the  fourth  day  of  lactation.  The 
formation  of  sulphureted  hydrogen  and  phosphoric  acid  in  milk 
results  from  the  splitting  up  of  casein. 

Hydrogen  sulphide  can  be  demonstrated  in  canned  milk  even  months  after  heating, 
whereas  in  sterile  bottled  milk,  under  the  influencee  of  light  and  in  the  presence  of 
oxygen,  the  sulphide  of  hydrogen  is  utilized  for  the  formation  of  water  and  sulphur. 

In  higher  heating  the  milk  becomes  brownish  through  caramel- 
ization  of  the  milk  sugar  and  the  lecithin  content  of  the  milk 

13 


194  Effect  of  Heat. 


diminishes,  which,  according  to  Kida,  may  be  seen  from  the  fol- 
lowing example: 

In  1000  c.  c.  of  milk,  lecithin  was  present  as  follows : 
Unheated  samples... 0.474 gm.    0.474    0.505    0.467    0.462    0.517 

Heated  to    75  deg. . .  .0.444  gm 

Heated  to    80  deg 0.420    0.467      

Heated  to    95  deg 0.349      

Heated  to  100  deg 0.351      

Over  100  deg.  C 0.401 

Diminishing  amt.  ...0.030  gm.     0.054    0.038     0.118     0.111     0.116 
In  percentage 6.33  11.39      7.52     25.27    21.22     22.17 

In  heating,  the  proteids  also  change,  peptone  is  formed  and 
tricalcium  phosphate  is  precipitated. 

The  original  ferments  are  especially  susceptible  to  the  influ- 
ence of  heat.  Through  heating  to  a  certain  temperature  the 
amylase,  the  peroxydase,  the  catalase  and  the  aldehyde  reductase 
disappear.  The  amylase  and  the  aldehyde  reductase  disappear 
even  at  a  temperature  of  65,  that  is  from  50-65  deg.  C.  Of  course 
milk  which  has  been  changed  in  this  way  by  heat  must  naturally 
be  judged  differently  from  a  nutritive  standpoint  than  raw  milk. 
Out  of  3,462  digestible  proteids  used  in  each  100  gm.  of  milk  there 
remained  undigested: 

In  unheated  milk 0.762  gm. 

In  heating  for  30  min.  to    80  deg.  C 1.153  gm. 

85  deg.  C....  1.493  gm. 

90  deg.  C....  1.420  gm. 

95  deg.  C....  1.540 gm. 

100  deg.  C....  1.719  gm. 

Experiments  by  Briickler,  Eeiner  and  Eichloff  showed  that 
dogs  fed  for  months  on  sterilized  milk  showed  a  good  nutritive 
condition,  and  some  of  them  even  manifested  a  greater  gain  in 
weight  than  the  control  dogs  fed  with  raw  milk,  but  the  latter 
were  brighter,  their  blood  was  richer  in  ash,  with  diminished  salt 
content;  it  contained  more  fibrin,  had  a  higher  specific  gravity, 
and  the  structure  of  their  bones  was  more  dense  and  richer  in 
ash.  The  bone  marrow  of  the  animals  fed  with  sterile  milk  was 
more  anemic,  the  periosteum  of  the  bones  separated  more  easily, 
and  at  times  hemorrhages  appeared  on  the  borders  of  the 
diaphyses,  such  as  occur  in  rachitis. 

The  nutritive  results  in  children  which  have  for  a  long  time 
been  exclusively  nourished  on  sterilized  milk  are  similar.  The 
infants  become  affected  with  infantile  scorbutus,  a  symptom  com- 
plex, which  is  known  to  the  physician  as  "Moller-Barlow  disease," 
and  which  disappears  when  raw  milk  is  provided. 

From  the  above  it  appears  that  high  prolonged  heating  of 
milk  should  be  avoided,  and  if  possible  the  advantages  derived 
from  the  heating  should  be  obtained  by  heating  the  milk  for  only 


Pasteurization   of  Milk.  195 


a  short  time  at  a  relatively  low  temperature,  which  when  properly 
applied  will  appropriately  destroy  the  bacteria. 

The  vegetative  bacteria  may  be  destroyed  by  subjecting  them 
to  the  influence  of  heat  at  60-70  deg.  C.,  for  one-half  hour,  or  to  a 
temperature  of  85  deg.  C.  for  a  half  minute;  on  the  other  hand 
it  is  known  that  spores  of  bacteria  not  infrequently  resist  a  tem- 
perature of  100  deg.  C.  and  over. 

In  practice  it  is  advisable  to  abstain  from  the  sterilization  of 
milk  with  high  degrees  of  temperature,  and  to  apply  pasteurization, 
since,  through  the  usual  method  of  sterilization  the  destruction  of 
all  germs  is  not  attained  and  the  disadvantages  are  too  apparent. 

The  wholesale  depots  may  be  provided  with  outfits  for  bottle 
pasteurization  and  milk  heating,  in  which  flowing  milk,  through 
the  influence  of  steam  on  heating  surfaces  may  be  brought  to  a 
temperature  of  85  deg.  C.  In  heating  bottled  milk  it  is  essential 
to  observe  that  the  milk  should  become  uniformly  heated  through- 
out ;  this  is  attained  by  shaking  the  milk  during  its  pasteurization. 
Following  this,  rapid  cooling  should  be  undertaken,  which  is  best 
accomplished  by  atomizing  pipes  which  cause  water  to  fall  upon 
the  hot  bottles  in  the  form  of  a  spray. 

The  apparatuses  in  which  the  milk  flows  over  heated  surfaces 
should  be  so  constructed  that  all  parts  of  the  milk  will  come  in 
contact  with  the  heated  surface,  making  the  heating  of  the  milk 
uniform  in  all  parts.  The  utilization  of  the  heat  in  some  of  the 
appliances  is  regulated  in  such  a  way  that  the  cold  inflowing  milk 
is  warmed  by  the  outflowing  pasteurized  milk,  the  latter,  however, 
being  cooled  subsequently.  Through  the  exchange  of  heat  from 
the  outgoing  stream  of  milk  about  one-half  of  the  required  heat 
may  be  saved.  The  efficiency  of  some  of  these  apparatuses  is 
enormous,  since  they  are  able  to  treat  from  5000  to  8000  liters  per 
hour. 

From  a  sanitary  standpoint  it  is  apparent  that  such  appara- 
tuses must  be  so  constructed  that  they  may  be  readily  cleaned 
mechanically,  since  improperly  cleaned  places  conduct  the  heat 
poorly,  and  may  give  rise  to  contamination  of  the  milk  with  putre- 
factive bacteria. 

In  pasteurization,  the  same  as  in  milk  production,  the  greatest 
stress  should  be  laid  on  immediate  and  thorough  cooling,  and  on 
keeping  the  milk  continuously  cool  until  its  consumption,  since 
otherwise  the  pasteurized  milk  will  become  spoiled,  and  will  un- 
dergo a  form  of  decomposition  which  is  very  undesirable  (espe- 
cially in  bottle  pasteurization).  Pasteurized  milk  decomposes 
through  multiplication  of  protein  splitting,  peptonizing  bacteria 
whose  spores  may  have  withstood  the  heating.  The  vegetative 
bacteria,  among  these  the  lactic  acid  producers,  are  mostly  de- 
stroyed, and  except  for  a  few  resistant  forms  of  spore  bearers  only 
heat-resisting  organisms  will  remain  viable,  but  these  forms  of 
bacteria  are  usually  harmless  (Rullmann,  Gerber  and  Wieske, 


196  Effect  of  Heat. 


Burri,  Russell  and  Hastings).  These  germs  decompose  proteids 
and  carbohydrates  by  forming  butyric  acid  with  gas  production, 
and  peptonizing  the  proteids.  Boiled  milk  decomposes  more  read- 
ily than  raw  milk  from  the  bacteria  which  contaminate  it  after  the 
heating  process. 

Relative  to  the  effects  of  pasteurization,  the  following  should 
be  noted :  As  a  result  of  the  effect  of  85  deg.  C.  the  bacterial  num- 
ber dropped  from  10,000,000  to  500  per  c.  c.  These  remaining 
organisms  however,  which  consist  principally  of  peptonizing  var- 
ieties, multiply  rapidly  to  very  great  numbers  if  the  milk  is  brought 
again  to  25  degrees  C.,  frequently  producing  changes  in  taste, 
which  becomes  bitter  and  irritating,  but  sometimes  without  mark- 
edly changing  either  the  appearance  or  taste. 

This  however  does  not  render  pasteurization  hazardous,  since 
it  is  possible  through  proper  handling  of  the  milk  to  prevent  these 
undesirable  processes.  The  marketing  of  pasteurized  milk  becomes 
dangerous  only  when  the  consumer  considers  that  pasteurized 
milk  being  free  of  germs  may  be  kept  indefinitely  under  almost 
any  circumstances  and  therefore  takes  less  care  of  pasteurized 
milk  than  he  would  of  the  raw  product;  besides  this  consumers 
repeatedly  heat  such  milk  and  thereby  diminish  its  nutritive  value 
more  and  more.  It  is  for  this  reason  that  various  authorities 
have  taken  action  against  the  indiscriminate  distribution  of  pas- 
teurized milk.  It  should  be  required  that  the  date  of  pasteuriza- 
tion be  indicated  on  each  bottle. 

A  statement  from  the  officials  of  the  city  of  Leipsic  asserts  that  pasteurized  milk  is 
not  more  valuable  than  raw  milk,  but  that  it  appears  to  be  of  lesser  value  on  account 
of  the  destruction  of  its  raw  condition  and  the  consequent  changes.  Any  manipulation 
of  milk  which  claims  to  extend  its  keeping  properties  by  several  hours,  and  which 
possibly  may  be  used  in  the  establishment  of  false  valuation  by  statements  that  the 
milk  has  a  lasting,  keeping  quality  and  a  freedom  from  bacteria,  is  directly  dangerous 
and  injurious  to  health  if  the  consumer  is  not  thoroughly  informed  with  regard  to  the 
effectiveness  and  limitations  of  pasteurization.  The  action  of  peptonizing  bacteria  in 
milk  that  has  been  pasteurized  is  pointed  out,  and  recommendation  is  made  against  the 
purchase  of  milk  which  was  pasteurized  more  than  three  days  previously.  The  official 
statement  al?o  calls  attention  to  Barlow's  disease,  and  to  the  dangers  attending  improper 
keeping  of  such  milk. 

Sometimes  pasteurized  milk  which  is  never  free  of  bacteria  is 
marketed  under  the  attractive  declaration  of  "free  from  disease- 
bacteria."  What  is  the  relation  of  pasteurization  to  such  a  claim 
as  this?  According  to  the  experiments  of  Forster,  van  Geuns,  de 
Mann,  Ringeling  and  Koning,  de  Jong,  de  Graaf,  and  Beck,  the 
disease-producing  bacteria  are  affected  differently  by  high  tem- 
peratures while  in  milk  than  when  in  bouillon  or  water.  Thus 
for  instance  heating  for  a  half  hour  at  70  deg.  C.  is  not  always 
sufficient  to  destroy  colon  bacteria.  Tubercle  bacilli  are  still  more 
resistant.  According  to  Kolle  and  Beck  they  are  not  destroyed 
with  certainty  even  when  subjected  to  heating  for  a  half  hour  at 
80  deg.  C.,  especially  not  when  they  are  isolated  from  the  influence 


Thermal   Death   Point   of  Bacteria.  197 


of  the  heat  by  the  formation  of  a  surface  scum  and  by  coagulation. 
De  Jong  concludes  from  his  experiments    (bottle  sterilization) : 

1.  That  heating  for  a  half  hour  at  71-72  deg.  C.  is  not  always 
sufficient  to  destroy  the  tubercle  bacilli  mixed  with  the  milk. 

2.  That  heating  even  to  a  higher  degree  does  not  always  give 
satisfactory   results   since   the    resisting  power   of  the   tubercle 
bacillus  varies. 

3.  The  designation  "free  from  disease-bacteria"  for  pas- 
teurized milk  is  false. 

4.  Those  who  desire  milk  free  from  tubercle  bacilli  must 
purchase  sterilized  milk,  provided  it  is  not  obtained  from  herds 
free  from  tuberculosis.     Bang,  de  Mann  and  Forster  obtained 
evidence  that  heating  to  85  deg.  C.,  for  three  minutes  destroys  the 
tubercle  bacilli,  a  fact  which  has  also  been  confirmed  by  the  work 
of  Weigmann  and  by  the  experiments  of  Tjaden,  Koske  and  Her- 
tel  under  conditions  which  prevail  in  large  distributing  plants  with 
milk  from  tuberculous  udders.     Other  non-spore-containing  dis- 
ease-producers in  milk  are  also  destroyed  at  this  temperature  pro- 
vided that  certain  conditions  do  not  prevent  proper  heating. 

[According  to  the  experiments  of  Rosenau,  it  is  evident  that 
the  tubercle  bacillus  in  milk  loses  its  infective  properties  for  guinea 
pigs  when  heated  to  60°  C.  and  maintained  at  that  temperature 
for  20  minutes  or  to  65°  C.  for  a  much  shorter  time.  It  should  be 
remembered  that  the  milk  in  the  tests  of  Rosenau  was  very  heavily 
infected  with  virulent  cultures,  which  was  indicated  by  the  prompt 
deaths  of  the  control  animals.  Milk  would  practically  never  con- 
tain such  an  enormous  amount  of  infection  under  natural  condi- 
tions. It  is  therefore  justifiable  to  assume  that  if  60°  C.  for  twenty 
minutes  is  sufficient  to  destroy  the  infectiveness  of  such  milk  when 
injected  into  the  peritoneal  cavity  of  a  guinea  pig,  any  ordinary 
market  milk  after  such  treatment  would  be  safe  for  human  use  by 
the  mouth  as  far  as  tubercle  bacilli  are  concerned.  These  results 
are  substantiated  by  the  findings  of  Versin,  Bonhoff,  Th.  Smith, 
Schroeder,  Russell  and  Hastings  and  Hesse. 

Relative  to  the  thermal  death  point  of  other  organisms  Rose- 
nau found  that  typhoid  bacilli  are  killed  in  milk  when  heated  to 
60°  deg.  C.  and  maintained  at  that  temperature  for  two  minutes. 
The  great  majority  of  these  organisms  are  killed  by  the  time  the 
temperature  reaches  59°  C.  and  few  survive  to  60°  C. 

The  diphtheria  bacillus  succumbs  at  comparatively  low  tem- 
peratures. Oftentimes  it  fails  to  grow  after  heating  to  55°  C. 
Some  occasionally  survive  until  the  milk  reaches  60°  C. 

The  cholera  vibrio  is  similar  to  the  diphtheria  bacillus  so  far 
as  its  thermal  death  point  is  concerned.  It  is  usually  destroyed 
when  the  milk  reaches  55°  C.,  only  once  did  it  survive  to  60°  C. 
under  the  conditions  of  the  experiments. 

The  dysentery  bacillus  is  somewhat  more  resistant  to  heat 
than  the  typhoid  bacillus.  It  sometimes  withstands  heating  at 


198  Effect  of  Heat. 


60°  C.  for  five  minutes.  All  are  killed  at  60°  C.  for  ten  minutes. 
However,  the  great  majority  of  these  micro-organisms  are  killed 
by  the  time  the  milk  reaches  60°  C. 

So  far  as  can  be  judged  from  the  meager  evidence  at  hand,  60° 
C.  for  twenty  minutes  is  more  than  sufficient  to  destroy  the  in- 
fective principle  of  Malta  fever  in  milk.  The  Micrococcus  meliten- 
sis  is  not  destroyed  at  55°  C.  for  a  short  time ;  the  great  majority 
of  these  organisms  die  at  58°,  and  at  60°  all  are  killed. 

Milk  heated  at  60°  C.  and  maintained  at  that  temperature  for 
twenty  minutes  may  therefore  be  considered  safe  so  far  as  con- 
veying infection  with  the  micro-organisms  tested  is  concerned. 

Ayers  states  that  the  best  method  of  pasteurization  at  the 
present  time,  and  the  one  which  should  be  used,  is  the  holder  proc- 
ess, in  which  the  milk  is  held  for  30  minutes.  For  this  process  a 
temperature  of  63°  C.  (145°  F.)  is  to  be  advised,  since  that  temper- 
ature gives  a  margin  beyond  that  sufficient  to  destroy  pathogenic 
organisms,  while  at  the  same  time  it  leaves  in  the  milk  the  maxi- 
mum number  of  lactic-acid-producing  organisms  which  cause  the 
souring  of  the  milk.  When  using  the  flash  process,  the  milk  should 
be  heated  to  at  least  160°  F.  Since  there  is  almost  always  a 
fluctuation  in  the  temperature  during  pasteurization,  care  should 
be  taken  to  see  that  the  temperature  never  drops  below  71°  C. 
(160°  F.)  in  the  flash  process.— Trans.] 

Exposure  at  50  degrees  of  temperature  for  15  minutes  or  at 
70°  C.  for  10  minutes  is  sufficient  to  destroy  the  virus  of  foot-and- 
mouth  disease.  The  virus  is  destroyed  instantaneously  at  85 
deg.  C. 

All  of  these  advantages  may  also  be  obtained  from  subjecting 
the  milk  in  the  household  to  heating  for  a  short  time  without 
'boiling,  when  through  occasional  stirring  the  formation  of  the 
scum  upon  the  surface  is  prevented.  Therefore  the  purchase  of 
raw  milk,  whose  fresh  condition  can  be  readily  controlled,  should 
be  generally  recommended,  and  the  destruction  of  bacteria  should 
then  be  carried  out  by  simple  heating. 

The  observation  recorded  by  Schut  appears  to  be  worthy  of  consideration,  namely 
that  relatively  low  temperatures  rapidly  destroy  bacteria,  when  applied  simultaneously 
with  a  lowering  of  the  pressure.  In  heating  the  milk  at  70  deg.  C.  the  disturbing  scum 
formation  was  omitted.  As  accepted  by  Sehut,  in  this  process  the  steam  penetrates 
into  the  body  of  bacteria,  which  explains  the  more  efficient  action  of  this  method. 

Experiments  which  aim  to  improve  the  keeping  qualities  of 
milk  by  the  addition  of  chemical  substances  are  very  numerous. 
In  addition  to  improving  its  keeping  qualities  the  retention  of  the 
raw  condition  of  the  milk  was  attempted.  This  does  not  refer  to 
the  adulterations  which  are  undertaken  by  dealers  for  fraudulent 
purposes,  or  which  are  carried  out  in  the  household,  and  it  should 
be  considered  that  all  additions  to  milk  without  subsequent  decla- 
ration are  equal  to  an  adulteration  of  food,  changing  it  to  a  spoiled 
product,  possibly  even  converting  it  into  material  injurious  to 
health. 


Preserving  Milk  with  Chemicals.  ^99 

At  that  the  additions  do  not  accomplish  the  purpose  for  which 
they  are  intended  in  the  dilutions  in  which  they  are  used  (Richter- 
boracic  acid),  or  they  diminish  the  utilization  of  milk  for  cheese 
production  because  they  inhibit  the  rennet  action.  Soda  or  bi-car- 
bonate  of  soda,  boracic  acid  and  borax,  more  rarely  salycilic  acid, 
and  recently  formaldehyde  are  mostly  used.  Adulterations  will 
not  be  discussed  here,  but  only  earnest  scientific  experiments  will 
be  taken  up,  in  which  the  accomplishment  of  an  actual  improve- 
ment in  milk  has  been  the  object  sought. 

1.  Budde  succeeded  in  improving  the  keeping  qualities  of 
milk  with  the  aid  of  peroxide  of  hydrogen.  The  milk  is  heated  to 
about  50  deg.  C.,  0.036  to  0.5%  H202  is  added  and  it  is  then  filled 
into  bottles  and  kept  for  several  hours  at  50  deg.  C. 

According  to  Lukin  it  is  possible  with  pure  peroxide  of 
hydrogen,  as  indicated  by  Budde,  to  give  the  milk  a  low  bacterial 
count,  or  render  it  free  of  bacteria.  Budde 's  method  has  not  at- 
tained an  extensive  use.  According  to  Chick,  Eosam,  Gordan, 
Bergmann  and  Hultmann,  Eicholz,  Nikoll  and  Duclaux  the  amount 
of  peroxide  of  hydrogen  recommended  by  Budde  is  not  sufficient 
for  the  satisfactory  destruction  of  bacteria  in  milk,  but  according 
to  Lukin  their  failures  were  due  to  the  use  of  impure  preparations 
of  peroxide  of  hydrogen.  Tubercle  bacilli  and  typhoid  bacilli 
were  not  destroyed  by  this  method.  If  the  authors  used  0.1%  of 
peroxide  of  hydrogen,  the  necessary  quantity  to  produce  steriliza- 
tion, then  the  milk  obtained  a  bitter  taste,  which  disappeared  only 
after  the  excess  of  hydrogen  peroxide  had  been  eliminated  by  cat- 
alase.  According  to  IJtz  a  small  quantity  of  peroxide  of  hydrogen 
is  retained  in  the  milk  even  when  used  in  the  quantities  recom- 
mended by  Budde.  De  Waele,  Sugg  and  Vandevelde,  who  worked 
with  0.3  and  0.4%  of  peroxide  of  hydrogen,  have  used  in  addi- 
tion small  quantities  of  defibrinated  blood  for  splitting  up  the 
retained  H202. 

Much  and  Rb'mer  employ  a  similar  method  of  preserving  milk 
which  has  been  obtained  under  special  precautions  as  to  cleanli- 
ness. The  milk  is  filled  into  sterilized  bottles,  mixed  with  0.1% 
of  peroxide  of  hydrogen,  and  kept  for  one  hour  at  52  deg.  C. 
For  the  destruction  of  the  H202  in  the  milk,  hepin,  a  catalase 
prepared  from  liver,  is  added  to  the  milk  before  its  consump- 
tion. Since  the  hydrogen  peroxide  milk  is  very  sensitive  against 
the  influence  of  light  (when  exposed  to  light  it  very  readily  be- 
comes bitter,  tallowy  and  rancid),  it  is  best  to  keep  it  in  green 
bottles  and  in  a  dark  place.  Even  with  these  precautions  a  change 
in  the  taste  may  become  apparent  after  two  weeks. 

Injurious  action  of  the  peroxide  of  hydrogen  if  used  in  these 
quantities  should  not  be  feared;  the  results  in  infant  feeding  are 
supposed  to  be  favorable. 

The  milk  which  is  freed  from  the  retained  peroxide  of  hydro- 
gen by  the  addition  of  hepin  should  be  immediately  used,  since  it 


200  Effect  of  Chemicals. 


is  no  longer  resistant  to  decomposition  through  bacterial  con- 
tamination, after  the  hepin  has  been  added. 

2.  Years  ago  von  Behring  recommended  the  preservation 
of  milk  by  formaldehyde.    Experiments  upon  animals  showed  that 
the  addition  of  formaldehyde  to  milk  in  the  proportion  of  1 :1250 
gave  it  no  properties  injurious  to  health  by  any  method  of  appli- 
cation (even  intravenously),  and  it  was  further  found  that  animals 
with  a  very  delicate  sense  of  smell  failed  to  recognize  the  presence 
of  formaldehyde  if  it  had  been  added  to  the  milk  in  a  dilution 
of  1 :10,000.    The  action  of  formaldehyde  in  such  dilution  is  quite 
marked.    The  addition  of  a  1 :10,000  dilution  postpones  coagulation 
for  many  days  (von  Behring,  Price  and  Schaps) ;  1:25,000  and 
1:40,000  prevents  coagulation  from  1  to  4  days    (Kolle).     The 
action  of  formaldehyde  was  found  to  be  more  effective  in  accord- 
ance with  the  cleanliness  of  the  natural  milk  and  this  action  ac- 
cording to  Rothschild  and  Metter  appears  to  result  from  the  fact 
that  the  lactic  acid  bacilli  chiefly  succumb,  whereas   the  other 
saprophytes  are  harmed  to  a  lesser  degree.     Tubercle  bacilli  are 
not  influenced  in  their  viability  by  these  dilutions. 

The  feeding  of  infants  for  weeks  with  formalin  milk  (addi- 
tions of  1 :25,000)  may  result  in  an  injury  of  the  kidney  epithelium 
of  the  children,  which  leads  to  the  elimination  of  albumin.  Ac- 
cording to  Baudini  the  rennet  pepsin  and  trypsin  action  may  be 
considerably  inhibited  by  formalin;  the  acidity  of  the  milk  is 
increased.  In  the  experiments  of  von  Behring  the  action  of 
formalin  depends  upon  its  effect  in  checking  the  development  of 
bacteria,  and  not  on  its  disinfecting  or  sterilizing  property.  A 
concentration  of  1 :25,000  up  to  1 :50,000  has  no  influence  on  the 
typhoid  and  colon  bacteria  and  staphylococci  (Vaughan  and 
Schaps).  Diphtheria,  colon  and  pyocyaneus  bacilli  have  not  been 
destroyed  even  in  dilutions  as  low  as  1 :5,000.  Tubercle  bacilli  are 
protected  by  their  waxy  covering  even  against  higher  proportions 
of  formalin,  and  as  a  matter  of  fact  formalin  is  used,  on  account 
of  its  action  on  other  bacteria,  for  the  purification  of  sputum  for 
the  purpose  of  cultivating  the  tubercle  bacilli  from  the  saliva. 
Formalin  milk  constitutes  a  food  which  should  be  designated  as 
spoiled  and  injurious  to  health. 

3.  Seiffert  worked  out  a  method  of  milk  preservation  in 
which   the  bactericidal   action   of  ultra-violet   rays   is   used   for 
sterilization  of  milk.     The  method  of  action  of  the  ultra-violet  rays 
has  not  yet  been  satisfactorily  explained.     According  to  Lobeck 
(cited  by  Grimmer)  the  exposure  of  water  to  such  rays  produces 
peroxide  of  hydrogen.     Grimmer  believes  that  the  latter  is  also 
formed  in  milk,  but  on  account  of  the  catalectic  factors  of  the  milk 
it  immediately  decomposes  again.    It  is  possible  that  the  forma- 
tion of  peroxide  of  hydrogen  constitutes  the  germicidal  power  of 
ultra-violet  rays.     The  milk  fat  is  not  changed   (Lobeck).     Ac- 
cording to  Dreier-Hansen  the  proteid  is  coagulated  after  a  pro- 


Ultra-violet   Rays.  201 


longed  exposure  of  milk  to  such  rays.  Seiffert  passes  the  milk  in 
broad  bottles  along  the  illuminating  bodies,  allowing  the  rays  to 
act  upon  the  milk  for  about  two  minutes.  He  employed  Leyden 
jars  fitted  with  aluminum  or  cadmium  points,  which  are  charged 
with  a  current  of  high  tension  through  an  inductor  which  dis- 
charges mutually.  Gerber  and  Hirschli  used  for  sterilization  the 
uviol  light  which  is  rich  in  ultra-violet  rays;  he  was  unable  how- 
ever to  demonstrate  a  marked  reduction  of  the  bacterial  content 
by  subjecting  a  layer  of  milk  of  1  mm.  thickness  to  its  influence, 
whereas  Finkelstein  and  Lobeck,  Henri  and  Stodel,  Billon  and 
Daguerre  obtained  good  results  with  the  ultra-violet  rays  from 
mercury  and  quartz  lamps.  According  to  Billon  and  Daguerre 
sterilization  may  also  be  accomplished  when  milk  is  exposed  to 
white  light  in  violet  glasses.  The  action  is  the  best  when  the  white 
light  is  split  up  by  a  prism. 

Romer  and  Sames,  who  also  conducted  experiments  on  the 
bactericidal  action  of  ultra-violet  light  proved  that  market  milk 
which  has  been  exposed  to  the  rays  of  a  Heraus'  mercury-quartz 
lamp  of  6  ampere  strength  in  a  quartz  alembic  (at  a  distance  of 
15  cm.  from  the  source  of  light  the  action  of  which  has  been  in- 
creased by  a  reflector)  caused  a  reduction  from  98,900  original 
bacteria  after  one  hour  of  exposure  to  16,500  bacteria;  after  1% 
hours  to  8750 ;  after  21 2  hours  to  2,050  bacteria.  The  taste  of  the 
milk  was  pronouncedly  irritating.  In  a  second  test  the  number  of 
bacteria  diminished  from  111,800  to  94,000  in  10  minutes,  and  to 
65,500  in  20  minutes.  On  the  surface  of  the  milk  a  yellowish  scum 
forms.  The  peroxydase  reaction  of  the  milk  is  destroyed  after  a 
prolonged  exposure  to  such  light. 

[The  experiments  of  Avers  and  Johnson  indicate  that  with 
quartz  mercury  vapor  lamps  of  the  present  power  and  construc- 
tion it  wolild  not  be  possible  commercially  to  completely  sterilize 
milk  by  the  ultra-violet  rays. 

It  might  be  possible  to  obtain  bacterial  reductions  as  great  as 
by  pasteurization  even  on  a  commercial  scale  by  the  use  of  large 
revolving  drums  and  a  number  of  lamps.  However,  in  milk  so 
treated  there  would  be  no  assurance  of  the  complete  destruction 
of  pathogenic  organisms  since  the  rays  do  not  seem  to  exert  any 
selective  destructive  action  on  vegetative  cells.  Of  course  since 
pathogenic  organisms  might  be  assumed  to  be  present  in  a  small 
number  in  proportion  to  the  total  bacteria  in  milk,  if  99.9  per  cent, 
of  the  organisms  present  were  destroyed,  it  might  be  assumed 
that  the  pathogenic  bacteria  would  be  destroyed.  This  process, 
however,  would  not  afford  the  same  security  as  does  proper  pas- 
teurization. Then,  again,  it  would  be  difficult  on  a  large  com- 
mercial scale  to  constantly  control  the  factors  which  influence  the 
bactericidal  action  of  the  rays. 

It  is  also  doubtful  if  the  lamps  could  be  made  to  successfully 


202  Effect  of  Chemicals. 


compete  with  the  present  method  of  steaming  milk  bottles  in  order 
to  partially  sterilize  them. 

From  these  experiments  it  appears  doubtful  if  ultra-violet 
rays  can  be  used  on  a  commercial  scale  to  replace  the  process  of 
pasteurization.  However,  it  may  be  possible  to  use  the  rays,  in 
combination  with  pasteurization,  in  the  preparation  of  a  special 
milk  with  a  low  bacterial  count,  provided  there  is  a  demand  for 
such  milk  in  limited  amounts  for  the  use  of  infants  and 
invalids. — Trans.] 

4.  Other  methods  of  preserving  milk  are  its  saturation  with 
carbonic  acid  under  strong  pressure,  its  ozonisation,  and  its  sterili- 
zation with  electrical  currents. 

The  carbonization  recommended  by  Hoffmann,  van  Slyke,  and 
Bosword,  the  ozonisation  advised  by  Dorn,  and  finally  the  steriliza- 
tion through  alternating  electric  currents  of  high  tension  recom- 
mended by  Guarini  and  Samarini  have  not  yet  attained  any  prac- 
tical significance. 

The  best  means  of  imparting  keeping  qualities  to  milk  are 
cleanliness  in  its  procurance;  the  only  method  of  preservation 
which  should  be  generally  permitted  for  milk  is  proper  cooling. 

This  concludes  the  theoretical  consideration  of  milk.  In  the 
following  chapter  the  method  of  control  of  milk  in  general  will  be 
discussed,  and  finally  the  method  of  milk  examination  will  be 
taken  up  with  emphasis  on  the  points  which  appear  especially 
important  in  the  examination  of  market  milk  and  for  the  ex- 
aminations of  individual  samples  of  milk. 


CHAPTER  IX. 

MILK    CONTROL. 

The  sanitary  police  control  of  foods  lias  advanced  greatly  in 
importance  during  recent  decades.  The  study  of  diseases  of 
nutrition  in  general  and  the  solution  of  the  etiology  of  these  affec- 
tions have  resulted  in  a  recognition  of  the  necessity  for  the  estab- 
lishment of  measures  relative  to  the  quality  of  food  substances, 
and  have  led  to  the  formulation  of  laws,  ordinances  and 
regulations. 

The  most  extensive  development  in  this  relation  is  shown  by  the  importance  of 
the  meat-inspection  law,  which  has  been  advanced  to  correspond  with  the  value  of  meat 
as  human  food.  Instead  of  controlling  the  marketable  meat  products  in  the  shops,  the 
most  important  part  of  the  inspection  is  placed  at  the  point  of  meat  production,  that 
is,  in  the  abattoirs.  With  the  exception  of  the  so-called  home  slaughtered  meats,  not 
a  single  pound  of  meat  is  consumed  or  used  for  food  products  in  Germany,  without 
being  first  subjected  to  inspection. 

The  meat  consumption  per  capita  in  Germany  in  recent  years 
has  amounted  to  from  103  to  110  Ibs.  In  addition  to  the  value  of 
the  meat  produced,  the  amount  of  milk  consumed  should  be  con- 
sidered, there  having  been  made  an  approximate  estimate  of  an  an- 
nual production  of  7  billion  gallons  of  milk,  the  smaller  portion  of 
which  is  utilized  as  drinking  milk,  the  larger  part  for  the  manufac- 
ture of  milk  products  as  cheese,  butter,  etc. 

According  to  statistical  compilations,  in  1905  the  quantity  of 
milk  consumed  per  capita  amounted 

in  Berlin  to  106.5  liters  (30  gal.) 
in  Munich  to  131.5  liters  (37  gal.) 
in  Hamburg  to  137.5  liters  (38  gal.) 

It  is  gratifying  to  note  that  the  consumption  of  milk  in  Munich 
has  increased  during  the  last  decade,  and  when  its  nutritive  value 
is  considered  its  low  cost  as  a  food  stuff  is  quite  apparent.  The 
amount  of  milk  and  meat  consumed  in  Munich  per  capita  is  as 
follows : 

1900 :  Milk  130  liters  (36  gal.)     Meat  81.8  kg.  (180  Ibs.) 
1904 :  Milk  131  liters  (37  gal.)     Meat  75.1  kg.  (165  Ibs.) 
1908 :  Milk  149  liters  (41  gal.)     Meat  85.9  kg.  (189  Ibs.) 
and  without  doubt  milk  consumption  will  still  continue  to  increase 

203 


204  Milk    Control. 


if  the  cost  of  all  other  foodstuffs  continues  to  rise.  There  aro  no 
means  by  which  the  nutrition  of  the  people  could  be  increased  to 
better  advantage  than  by  increasing  their  consumption  of  milk, 
since  it  has  not  yet  reached  the  high  point  warranted  by  the  value 
of  milk  as  a  nutritive  substance. 

From  the  various  discussion  in  this  work,  the  importance  of 
supplying  consumers  with  milk  of  good  quality  is  apparent.  An 
increase  in  milk  consumption  is  of  equal  importance  to  the  interest 
of  the  nutrition  of  the  people  and  to  the  interest  of  agriculture. 
This  increase  however  can  only  be  obtained  when,  in  addition  to 
an  educational  propaganda  regarding  the  nutritive  value  and  cost 
of  milk,  care  is  taken  to  rectify  the  generally  existing  evils  attend- 
ing its  production,  by  which  means  the  milk  will  be  brought  up  to 
a  standard,  which  may  reasonably  be  required  of  any  food.  There- 
fore it  should  not  only  be  unadulterated  but  must  be  produced  and 
delivered  in  a  clean  manner,  in  an  unspoiled,  fresh  condition,  and 
possess  no  disease-producing  properties. 

The  important  significance  of  healthy  milk  as  food  for  the  people,  especially  for 
infants,  has  been  emphasized  by  physicians,  hygienists  and  veterinarians  in  numerous 
special  articles,  which  have  argued  for  and  against  the  desirability  of  gaining  nutrition 
through  the  use  of  market  milk.  Public  interest  and  private  philanthropy  have 
accomplished  a  great  deal  of  good  by  the  establishment  of  infant  milk  depots.  Such 
establishments  are  frequently  attached  to  the  abattoirs,  and  are  conducted  under  the 
successful  direction  of  veterinarians.  It  is  impossible  to  enter  here  into  a  discussion 
of  such  establishments,  since  this  field  constitutes  only  a  small  branch  of  the  great 
question  of  the  milk  supply. 

While  the  determination  of  the  causes  of  the  so-called  dis- 
eases of  nutrition  may  not  yet  be  sufficiently  clear,  the  general  and 
local  surroundings  of  the  patient  or  other  conditions  may  influence 
the  course  of  these  diseases.  This  is  particularly  true  in  summer 
mortalities  of  children,  as  in  these  diseases  various  conditions,  such 
as  want  of  natural  nutrition,  faulty  housing,  etc.,  may  all  play  a 
part  as  factors.  Nevertheless,  from  the  experience  of  specialists 
the  conclusion  must  be  drawn  that  a  strict  sanitary  police  con- 
trol must  be  established  in  order  to  protect  human  health  as  much 
as  possible  from  the  ills  occasioned  by  dangerous  milk. 

Such  harm  may  result  from  the  consumption  of: 

1.  Milk  from  diseased  animals, 

2.  Milk   originally  wholesome   but  which  has   been   subse- 
quently contaminated  with  bacteria  pathogenic  for  man, 

3.  Milk,  which  has  been  spoiled  by  any  kind  of  decomposi- 
tion, or  which  is  beginning  to  spoil, 

4.  Milk  containing  chemical  preserving  substances. 

These  are  briefly  the  points  which  in  themselves  prove  the 
value  of  hygienic  control  of  the  milk  traffic,  and  their  elimination, 
with  as  much  consideration  as  possible  for  the  economic  impor- 
tance of  the  various  factors,  must  be  constantly  kept  in  mind. 

A  proper  execution  of  sanitary  police  regulations  governing 
milk  traffic  is  not  only  of  importance  for  the  health  of  the  people 


Advantages    of    Milk    Examinations.  205 

but  attains  even  greater  value  for  the  milk  industry  and  general 
agriculture  through  the  indirect  advantages  which  result  from 
their  enforcement,  such  as  the  improvement  of  the  herds,  etc. 
Measures  which  are  in  perfect  accord  with  the  hygienic  require- 
ments of  milk  traffic,  are  at  present  enforced  by  most  cities,  which 
have  adopted  various  forms  of  ordinances  and  laws  to  cover  this 
subject.  Some  of  the  states  and  the  federal  government  also  pro- 
vide for  certain  additional  control. 

The  milk  control  stations  of  several  cities  in  Germany  have 
attempted  to  produce  an  improvement  of  the  milk  traffic  by  the 
establishment  of  proper  ordinances.  Even  the  best  organized 
stations  confine  themselves  almost  entirely  to  the  control  of  the 
finished  product  offered  for  sale,  and  therefore  they  are  limited 
to  the  examination  of  samples.  If  the  existing  distribution  of  milk 
and  extension  of  deliveries  in  large  cities  are  considered  it  would 
require  an  army  of  officials  to  take  samples  and  examine  them,  in 
order  to  test  all  the  milk  delivered  to  ascertain  its  value  as  food. 

Even  in  the  eventual  centralization  of  the  milk  traffic,  ap- 
propriate examination  of  market  milk  from  a  hygienic  standpoint 
will  be  impossible,  since  in  each  shipment  too  many  questions 
would  have  to  be  solved,  and  besides  this,  we  have  not  at  our  com- 
mand reliable  methods  for  examining  the  finished  market  milk 
rapidly  and  thoroughly. 

The  advantages  of  market  milk  examinations,  which  should 
not  be  underestimated,  consist  in  the  fact  that  it  is  possible  to 
detect  gross  neglect  and  wilful  violations,  by  which  in  many  cases 
guilty  parties  may  be  held  responsible.  The  knowledge  that  he 
is  under  observation,  and  the  fear  of  punishment  compel  even  the 
most  indolent  milkman  and  dealer  to  give  increased  attention 
to  production  and  handling,  including  transportation.  In  some 
cities  of  Germany  a  great  deal  has  been  accomplished  in  the  con- 
trol of  market  milk,  but  an  effective  improvement  is  prevented  by 
the  existing  methods  of  milk  officials.  Whatever  has  been  ac- 
complished through  the  control  of  market  milk,  it  is  slight  when 
compared  with  the  requirements  of  the  law  and  regulations.  If 
milk  control  is  confined  in  a  one-sided  way  only  to  adulteration, 
preservation  and  to  the  dirt  content,  or  to  fermentation  tests  and 
acid  content,  as  they  are  mostly  practiced,  it  is  hardly  possible  to 
expect  proper  improvement  from  a  hygienic  standpoint. 

Food  chemists  have  been  the  chief  officials  engaged  in  milk 
control  up  to  the  present  time,  since  the  principal  stress  has  been 
laid  on  the  detection  of  adulteration  or  of  attempts  to  improve 
milk  by  the  use  of  preservatives.  The  author  considers  it  as  ab- 
solutely essential  that  this  field  of  control  should  continue  in 
charge  of  chemists,  since  the  physico-chemical  properties  of  milk 
require  a  great  amount  of  special  training  if  the  results  obtained 
by  examination  are  to  be  subjected  to  critical  judgment.  This 
however  does  not  infer  that  veterinarians,  physicians  or  other 


206  Milk   Control. 


persons  who  have  obtained  special  training  have  not  the  same 
right  to  take  up  the  work  against  violators.  It  is  immaterial  who 
executes  the  work  if  it  is  only  carried  out  properly.  Chemists, 
veterinarians  and  physicians  have  their  special  sphere  of  activity 
in  milk  control,  and  all  should  work  in  harmony  that  they  may 
accomplish  the  desired  results,  each  profession  exerting  all  its 
power  towards  improvement  of  the  milk  supply  from  the  time 
of  its  production  until  its  distribution  to  the  consumer.  It  is 
deemed  advisable  to  introduce  here  a  short  description  of  milk 
control  in  the  City  of  Munich : 

The  beginning  of  control  in  Munich  can  be  traced  back  to  1834.  Police  authorities 
brought  to  the  police  physician  samples  for  examination.  With  the  taking  over  of  food 
inspection  by  the  magistrate  in  1862,  market  inspectors,  and  in  1876  district  inspectors, 
were  detailed  to  take  samples  and  to  make  the  preliminary  examinations  under  the 
direction  of  district  veterinarians.  The  latter  were  required  to  carry  out  the  scientific 
examinations  and  to  pass  judgment  on  the  samples. 

By  an  agreement  of  hygienists,  food  chemists,  dairy  experts  and  agriculturists, 
the  latest  local  police  measures  were  inaugurated  in  1906,  and  at  the  same  time  the 
inspection  forces  were  reorganized. 

The  city  was  divided  into  six  control  districts,  and  the  inspectors  assigned  to  these 
districts  had  to  carry  out  the  requirements  of  the  authorities  and  the  experts  relative 
to  the  supervision  of  the  milk  traffic.  The  scientific  part  of  the  inspection  is  conducted 
in  the  corresponding  divisions  of  the  examining  station,  that  is  in  the  chemical  and  the 
veterinary  bacteriological  divisions.  Assistant  inspectors  are  assigned  to  the  inspectors 
for  aiding  them  in  the  work  and  for  the  transportation  of  the  samples.  The  inspectors 
are  required  to  supervise  the  execution  of  the  regulations  and  to  report  any  violations 
of  these  measures  to  the  milk  control  station.  The  supervision  should  be  adapted  as 
far  as  possible  to  the  hours  in  which  the  business,  sale  and  operation  of  the  milk 
establishments  are  carried  on,  but  may  be  carried  out  at  all  hours  of  the  day  and  night, 
and  it  should  be  so  regulated  that  the  dairies  at  no  time  could  feel  safe  from  the  restraint 
of  supervision.  The  duty  includes: 

1.  The  control  of  and  supervision  over  all  milk  brought  into  the  city,  all  milk 
which  is  in  traffic  within  the  city,  all  transportation  containers,  all  dairies,  milk  shops 
and  production  establishments  within  the  city  limits,  and  the  taking  of  samples. 

2.  The  procuring  of  necessary  milk  samples  for  examination,  both  from  stable 
and  salesroom,  and  of  other  material  necessary  for  evidence. 

3.  Conducting  research  work  in  individual  cases,  and  making  out  reports  and 
complaints. 

All  collected  samples  of  milk,  samples  of  other  food  substances  which  are  sold 
in  the  dairy,  milk  cans  which  do  not  correspond  with  the  regulations,  various  containers 
in  which  the  milk  is  kept,  measured  and  sold  should  be  submitted  at  the  milk  control 
station  for  opinion.  A  report  should  be  made  on  the  fittings  and  condition  of  the 
rooms  and  premises  where  the  milk  is  stored,  and  from  which  it  is  distributed.  The 
transportation  of  the  milk  samples  to  the  official  milk  control  station  should  be  accom- 
plished immediately  after  the  sample  is  procured.  A  preliminary  examination  precedes 
the  taking  of  samples  by  the  inspectors,  which  consists  in  an  examination  by  the  senses 
(appearance,  odor),  and  in  the  use  of  the  lactodensimeter  and  thermometer.  The  trans- 
mission of  the  samples  to  the  scientific  division  is  accompanied  by  forms  on  which  the 
results  of  the  preliminary  tests  are  indicated,  and  they  also  give  the  date,  hour,  place 
of  collection,  origin  of  the  sample,  name  of  the  dealer  or  producer,  number  of  the 
sample,  and  its  relation  to  a  certain  case. 

The  samples  are  immediately  examined  in  the  scientific  division,  the  inspectors 
are  informed  of  the  results  as  soon  as  possible,  and  their  subsequent  procedure  in 
special  cases  is  indicated  by  the  recommendations  of  the  experts  and  the  director  of  the 
station. 

If  stable  control  and  the  taking  of  samples  in  a  stable  outside  of  the  city  limits 
appear  necessary,  or  if  such  are  suggested  by  the  scientific  workers  of  the  official  milk 
control  station,  the  inspector  obtains  these  samples  after  obtaining,  through  the  city 
authorities,  permission  to  go  upon  the  premises.  In  taking  samples  in  a  stable  the 
principal  stress  must  be  laid  on  the  dairy  management  and  therefore  preliminary  tests 
of  the  samples  taken  in  the  stable  are  eliminated.  The  scientific  experts  attach  their 


Co-operation    of    Officials.  207 


opinion  to  the  reports  of  the  inspectors,  the  full  report,  with  the  result  of  the  researches, 
being  transmitted  through  the  official  control  station  to  the  magistrate,  who,  depending 
on  the  case,  transmits  the  material  to  the  proper  courts. 

The  separation  of  the  laboratories  into  a  chemical  and  a  bacteriological  division 
has  already  been  briefly  mentioned.  The  chemical  division  examines  for  simple  and 
combined  adulteration  by  the  addition  of  water,  removing  of  the  cream,  or  both,  by 
establishing  the  specific  gravity,  the  fat  contents,  calculating  the  amount  of  total 
solids,  and  the  fat-free  solid  content,  determining  the  refraction  index  of  the  milk 
serum  by  the  nitrate  test,  testing  for  the  degree  of  acidity  and  testing  for  other 
chemical  adulterations.  The  bacteriological  division  examines  as  to  fitness  for  eon- 
sumption  by  establishing  the  purity,  odor,  taste,  consistence,  age  and  freshness,  the 
raw  condition,  intermixing  with  secretion  of  animals  with  affected  udders,  etc.  The 
procedures  of  each  division  are  kept  separate  as  much  as  possible,  and  this  separation 
of  the  divisions  has  proven  of  splendid  advantage.  Co-operation  between  these  divisions 
when  the  work  overlaps,  and  mutual  support  aid  in  the  success. 

Owing  to  the  activity  of  the  official  milk  control  station  it  was 
soon  noticed  that  marked  adulterations  had  become  very  rare, 
and  that  objections  and  condemnations  on  account  of  gross  con- 
tamination were  reduced  to  a  minimum.  Considerable  objection 
still  exists  relative  to  the  transportation  cans  which  are  frequently 
used  in  a  most  insanitary  condition.  The  regulations  relative  to 
the  proper  closing  of  the  cans  are  now  almost  uniformly  observed. 
The  acid  content  of  the  milk  is  only  exceptionally  increased  by 
fermentation,  and  the  spoiled  milk  originates  usually  from  milk 
collecting  establishments  and  cheese  factories,  whereas  individual 
producers  as  a  rule  supply  fresh  milk.  The  increased  degree  of 
acidity  is  traced  in  most  instances  to  improper  cooling,  dirty  trans- 
portation cans,  mixing  of  fresh  and  old  milk  and  adulteration  with 
skimmed  milk.  Preserving  agents  scarcely  ever  come  into  con- 
sideration in  Munich. 

It  is  to  be  regretted,  however,  that  the  limits  of  milk  control 
activities  have  apparently  been  attained,  in  so  far  as  they  concern 
the  testing  of  milk  ready  for  consumption.  Nevertheless,  attempts 
have  been  made  by  extending  the  control  to  the  stable  and  to  the 
producing  animal  in  order  to  further  improve  the  milk  supply.  In 
certain  cases  good  results  have  been  obtained  through  giving  in- 
structions and  warnings  as  to  the  requirements,  or  at  least  in  ad- 
vising the  adoption  of  all  precautions  which  are  possible  in  prac- 
tice, for  instance  in  the  streptococcic  mastitis  question,  which  this 
city  was  first  to  take  up  on  practical  lines  on  a  large  scale.  The 
results  attained  are  by  no  means  to  be  underestimated,  but  while 
there  is  no  doubt  that  with  the  hard  battles  considerable  results 
have  been  obtained  for  the  moment  among  a  small  percentage  of 
the  producers,  still  no  one  can  offer  a  guarantee  that  even  on  the 
morrow  the  same  conditions  will  not  prevail  as  formerly,  and  in 
this  lies  the  insufficiency  of  market  milk  control  and  of  the  system 
of  taking  samples  from  time  to  time.  In  the  future  other  measures 
will  have  to  be  given  consideration  in  sanitary  milk  inspection,  if 
it  is  desired  that  conditions  which  are  frequently  intolerable,  and 
which  prevail  at  present  in  the  milk  industry,  should  be  eliminated. 

A  guarantee  of  good  and  harmless  quality  for  market  milk 


208  Milk    Control. 


forms  an  absolute  hygienic  requirement,  and  at  the  same  time  it 
is  the  prerequisite  for  increasing  milk  consumption  to  its  full  ex- 
tent. This  can  be  attained  only  through  strict  regulation  ami 
flawless  supervision  of  the  milk  from  the  beginning  of  its  produc- 
tion up  to  the  time  of  its  delivery,  taking  advantage  of  the  great 
progress  which  has  been  made  by  science  in  recent  times. 

Milk  hygiene  must  commence  in  the  stable.  A  perceptible 
step  in  advance  is  gained  by  the  introduction  of  stable  super- 
vision. The  preliminary  requirements  for  the  production  of  un- 
objectionable milk  are  healthy  milking  animals,  healthy  udders, 
healthy  milkers  and  clean  utensils  and  surroundings.  In  this  in- 
stance the  veterinarian  is  the  proper  counsellor,  his  preliminary 
training  offering  the  necessary  assurance  that  these  requirements 
for  well-managed  dairy  business  will  be  fulfilled.  Besides  the  ex- 
amination of  the  health  of  the  cows,  the  supervision  must  be  ex- 
tended to  the  care  of  the  animals,  stable  conditions,  and  the  keep- 
ing and  feeding  of  the  animals.  The  necessity  for  the  most  strin- 
gent cleanliness  in  milking  and  for  the  careful  preparation  of  the 
milk  by  means  of  filtration,  and  cooling  must  always  be  impressed 
upon  the  dairyman,  as  well  as  the  necessity  for  satisfactory 
transportation. 

Some  hygienists  consider  the  processes  of  decomposition 
brought  on  by  contamination  and  improper  treatment  of  milk  as 
especially  important  causes  for  the  rapid  spoiling  of  milk.  The 
author  considers  that  their  special  significance  should  be  laid,  in 
cases  of  milk  poisoning  the  same  as  in  meat  poisoning,  to  those 
disease-producers  and  their  products  which  prove  toxic  in  the 
animal  body,  and  which  originate  in  the  milk-producing  animal. 
The  veterinarians  prove  their  value  in  sanitary  police  supervision 
of  milk  production,  by  seeing  that  the  cities  are  supplied  with  good 
milk,  suitable  as  food  for  infants,  and  by  watching  the  dairy  indus- 
try. This  supervision  at  the  site  of  production  produces  better 
results  than  the  most  painstaking  and  well  organized  inspection  of 
the  finished  product.  The  great  dangers  which  threaten  man 
through  the  causative  agents  of  septic  metritis,  acute  and  chronic 
mastitis,  enteritis,  etc.,  are  considerably  reduced.  The  control 
of  the  milk  traffic  and  milk  industry  requires  especially  the  co- 
operation of  all  factors  which  come  into  consideration.  Until  uni- 
form regulations  for  sanitary  police  supervision  are  established  it 
will  remain  the  duty  of  veterinarians  and  physicians  to  point  out 
the  importance  of  hygienic  measures  to  the  producers  through  con- 
tinuous education,  indicating  also  the  economic  advantages  which 
may  be  gained  for  their  own  interests.  In  northern  Bavaria  the 
supervision  of  stables,  dairies  and  distributing  stations  has  already 
been  inaugurated  by  the  employment  of  district  dairy  inspectors. 

Through  periodical  stable  inspections  considerable  advance- 
ment could  be  made  at  the  present  time.  This  supervision  should 
not  only  include  the  so-called  certified  milk  or  infants'  milk,  but 


Supervision    of    Milk    Production.  9Q9 


also  the  production  of  all  milk  consumed,  since  the  largest  pro- 
portion of  the  parents  of  infants  and  consumers  in  general  cannot 
purchase  certified  milk,  and  the  children  of  this  class  who  cannot 
afford  to  buy  certified  milk  are  the  ones  principally  exposed  to  the 
dangers  of  infant  mortality.  Such  classifications  of  milk  may  be 
of  advantage  to  the  milk  trade,  but  they  must  not  be  taken  into 
consideration  by  sanitary  officials  who  are  supervising  the  milk 
traffic.  We  are  clear  with  regard  to  the  ultimate  aims  which  we 
must  bear  in  mind  in  the  sanitary  police  supervision ;  whether  these 
aims  will  ever  be  realized  is  a  question  of  economic  and  social  con- 
ditions. At  the  present  time  the  attainment  of  the  ideal  goal  of 
flawless  supervision  of  milk  from  its  production  to  its  consumption 
is  made  very  difficult  by  these  very  conditions.  As  long  as  the 
cheapness  of  milk  as  a  food  product  for  the  masses  stands  in  the 
foreground  in  the  interest  of  the  people,  a  place  in  which  it  actually 
must  stand,  a  proper,  thoroughly  organized  control  of  the  pro- 
duction can  hardly  be  inaugurated. 

Recommendations  for  such  control  have  teen  made  by  Meinert  and  others,  and 
recently  by  Schern.  For  an  effective  execution  of  control  over  the  production  of  milk, 
supervision  must  be  established  in  both  city  and  country.  Milk  is  produced  not  only 
in  the  country  but  also  in  the  city.  All  milk  produced  must  be  subjected  to  uniform 
control.  Within  these  districts  of  control  the  milk-producing  cities  should  therefore 
be  included.  A  veterinarian  periodically  examines  the  dairy  herds  and  the  milk  of 
each  animal,  the  individual  animal  in  these  districts,  etc.,  without  previously  giving  notice 
to  the  owner  of  the  animals  as  to  the  time  of  the  inspecton.  In  this  inspection  the 
milkers  are  also  observed  as  to  their  state  of  health.  The  procured  milk  is  examined 
to  see  whether  it  is  clean  and  sufficiently  cooled.  The  stables  are  examined  to  determine 
whether  they  meet  the  requirements  as  to  light,  ventilation  and  cleanliness.  The  control 
of  production  is  linked  with  the  supervision  of  transportation  in  certain  milk-collecting 
places,  and  finally  the  inspection  of  the  dealers  at  the  place  of  consumption  follows. 
Such  a  complete  supervision  is  not  considered  possible  in  practice  without  considerable 
increase  in  the  cost  of  the  product,  and  this  should  and  must  be  avoided.  The  sanitary 
milk  officials  will  have  as  their  most  important  duty  the  finding  of  ways  and  means  for 
the  practical  execution  of  supervision,  which  may  be  accomplished  without  great 
economic  losses  of  production  and  efficiency,  and  without  injuring  the  other  factors 
in  the  milk  industry.  Meinert  believes  in  the  possibility  of  supervising  the  places  of 
production  under  supervision  of  the  state,  by  the  appointment  of  physicians,  veterinarians 
and  practical  agriculturists  for  this  purpose. 

For  each  township  the  milk  producers  should  select  trustworthy  men  as  supervisors, 
who  by  means  of  frequent  examinations  at  the  time  of  milking  should  -convince  them- 
selves of  the  manner  in  which  the  requirements  of  the  legislative  measures  are  being 
observed.  The  activity  of  these  supervisors  should  be  principally  along  educational 
lines.  These  men  should  call  the  attention  of  the  owners  to  existing  deficiencies  in 
the  management  of  the  dairy,  they  should  offer  remedies  to  eliminate  these  deficiencies, 
and  after  the  lapse  of  a  certain  time,  they  should  satisfy  themselves  that  their  advice 
has  been  carried  out.  In  case  of  disease  of  the  dairy  cattle  it  should  be  reported  to 
a  veterinarian  for  consultation  and  judgment.  The  supervisors  should  be  instructed  as 
to  their  duties  by  the  official  veterinarians.  Creamery  corporations  could  select  their 
own  supervisors  instead  of  depending  on  the  local  supervisors  for  the  inspection  of  the 
dairies  producing  milk  for  their  plants.  Larger  establishments  could  voluntarily  subject 
themselves  to  direct  state  control.  Besides  this  practical  supervision,  the  district 
veterinarian  should  examine  the  animals  every  three  months  as  to  their  condition  of 
health,  and  judge  the  character  of  their  milk.  Persons  who  are  connected  with  the 
procuring  and  handling  of  milk  should  be  placed  under  the  control  of  an  official  physician. 
The  producers,  supervisors,  milkers,  and  all  persons  connected  with  the  dairy  should 
be  examined  as  to  the  possibility  of  their  transmitting  human  diseases  to  the  consumer 
through  the  milk  acting  as  an  intermediate  host,  and  the  supervisors  should  report  their 
observations  as  to  any  sickness  among  the  attendants  to  the  physician  in  authority. 
The  entire  system  is  subject  to  control  bv  the  state,  which  appoints  its  own  officials 
for  larger  districts  to  carry  out  the  supervision  of  the  work. 
14 


210  Milk    Control. 


It  must  always  be  considered  that  the  populace  has  an  interest 
not  only  in  the  procurance  of  unadulterated  and  unspoiled  milk, 
but  also  in  having  the  milk  marketed  at  such  a  price  that  it  may 
remain  accessible  as  a  product  of  consumption  for  the  masses,  and 
if  possible  its  consumption  should  be  increased.  Accordingly  too 
far-reaching,  stringent  requirements  should  be  avoided,  as  well  as 
all  requirements  that  cannot  be  met  by  the  prevailing  condition  of 
production,  on  account  of  financial  and  technical  grounds.  Healthy 
dairy  cattle  and  the  best  possible  cleanliness  of  the  stables  and 
surroundings  are  more  important  than  special  feeding  regulations, 
or  requirements  for  stable  buildings  which  the  small  farmer  is  not 
in  a  position  to  adopt.  In  order  to  prevent  too  stringent,  or  one- 
sided requirements  altogether,  the  adoption  of  a  uniform  standard 
would  be  necessary  for  the  entire  country,  and  each  state  could 
establish  its  own  regulations  which  would  conform  with  the  con- 
ditions of  that  particular  locality.  The  introduction  of  the  terms 
" inferior  value"  and  "conditionally  passed"  for  certain  low 
grades  of  milk  would  reduce  the  economic  loss  which  results  from 
the  use  of  the  terms  "spoiled,"  and  "injurious  to  health." 

If  stable  inspection  is  inaugurated,  a  thorough  organization 
may  conduct  a  supervision  by  which  the  owners  of  small  herds  can 
also  comply  with  the  requirements.  The  present  system  of  milk 
inspection  not  infrequently  fails  to  include  such  small  dairies  be- 
cause the  supervision  of  the  entire  milk  traffic  is  extremely  dif- 
ficult, but  with  the  introduction  of  stable  inspection  the  enforce- 
ment of  hygienic  requirements  that  shall  include  the  small  pro- 
ducer will  be  found  to  be  not  only  practicable,  but  also  very  de- 
sirable. Dairy  associations  and  contractors  with  co-operative 
creameries  should  regulate  fluctuations  of  deliveries  and  consump- 
tion, so  as  to  provide  the  best  possible  utilization  of  the  excess  of 
production,  or  the  milk  which  has  been  declared  by  the  city  in- 
spectors as  unfit  for  drinking  purposes  may  be  conditionally  passed 
if  designated  as  inferior  milk. 

Such  a  system  has  been  adopted  by  the  dairy  association  of 
Hamburg,  in  order  to  meet  the  economic  losses  caused  by  the 
stringent  enforcement  of  the  milk  inspection  regulations. 

The  author  believes  that  with  legislative  regulation  of  milk 
inspection,  and  especially  with  supervision  of  the  production,  it 
will  be  possible,  even  with  the  newly  created  conditions,  to  supply 
the  population  with  good,  clean,  wholesome  milk  at  relatively  low 
prices.  With  good  will  and  co-operative  work,  as  well  as  with  con- 
siderate enforcement  of  the  regulations,  the  desired  goal  may  pos- 
sibly be  reached  within  a  short  period  of  time. 


CHAPTER  X. 

MILK  INSPECTION, 
(a)  Taking  of  Samples. 

1.  Market  Milk.    The  taking  of  the  sample  must  take  place 
only  after  the  fat  of  the  cream  gathered  during  transportation  has 
been  sufficiently  distributed  through  shaking  or  stirring.    Especial 
attention    is    required   when    separation   has    occurred   through 
freezing. 

2.  Stable  Samples.    The  inspector  who  takes  the  sample  must 
have  his  whole  attention  directed  to  the  production  and  handling 
of  the  milk,  as  the  people  suspected  of  adulteration  often  display 
unbelievable  slyness  in  order  to  deceive  the  inspector.     Particular 
care  should  be  taken  that  the  mixing  tank  or  vat  does  not  leak, 
that  the  milk  pails  and  other  vessels  do  not  contain  wash  water, 
and  that,  during  the  milking,  the  milk  is  not  adulterated  with  water 
from  bottles  hidden  in  the  clothing  of  the  milkers ;  it  is  important 
that  the  milking  should  be  complete. 

If  nitrate  has  been  found  in  a  suspected  sample,  a  water  test 
for  nitrates  should  be  made  from  each  well  at  the  place  of 
production. 

Only  after  milking,  are  inquiries  to  be  made  regarding  the 
feeding,  keeping,  care,  and  condition  of  the  individual  animals,  etc. 

The  stable  samples  must  be  thoroughly  mixed. 

3.  At  least  i/2  liter  should  be  taken  from  each  market  or 
stable    sample,    in    order    to    have    sufficient    material    for    all 
examinations. 

4.  When  the  samples  have  to  be  carried  a  long  distance  to 
the  place  of  examination,  they  must  be  preserved  with  0. 1%  forma- 
lin.    For  chemical  examinations  0.1%   of  potassium  bichromate 
is  permissible,  which  is  obtained  by  the  addition  of  a  1%  solution 
to  100  parts  of  milk.     The  addition  must  always  be  stated. 

For  bacteriological  examinations,  the  preservation  of  the  sam- 
ple is  not  permitted,  except  in  cases  where  a  microscopical  exam- 
ination only  is  desired  for  the  determination  of  inflammations  of 
the  udder  or  the  presence  of  tuberculosis. 

211 


212  Milk.  Inspection. 


5.  The  sample  bottles  must  be  filled  up  to  the  neck,  in  order 
to  prevent  the  formation  of  butter  during  transportation. 

6.  The  bottles  should  be  closed  so  that  an  unauthorized  open- 
ing is  excluded. 

The  transportation  to  the  place  of  examination  must  take 
place  as  soon  as  possible  after  the  taking  of  the  samples,  and  if 
transported  by  rail,  sufficient  packing  should  be  provided  to  pre- 
vent breakage  of  the  bottles. 

If  samples  are  desired  from  individual  cows  and  not  market 
or  mixed  milk  samples,  smaller  amounts,  for  instance,  100  gms. 
or  less,  are  sufficient,  provided  that  only  an  examination  for  in- 
flammation of  the  udder  is  involved.  With  samples  taken  for 
chemical  examination  from  individual  cows,  a  complete  milk- 
ing is  necessary  for  satisfactory  results.  If  examinations  as  to 
changes  of  milk  through  diseases  are  to  be  made,  at  least  y2  liter 
must  be  sent  in  from  each  milking  until  the  day  after  recovery. 
In  certain  cases,  for  instance,  with  emergency  inoculation  in  foot- 
and-mouth  disease,  the  taking  of  samples  must  begin  before  the 
inoculation  and  continue  until  complete  recovery. 

When  examinations  for  inflammation  of  the  udder  are  desired, 
the  sample  of  milk  may  be  poured  into  a  reagent  glass  by  means  of 
a  dipper,  which  must  be  thoroughly  cleansed  after  each  sample, 
or,  the  samples  are  taken  in  such  a  manner  that  in  pouring  the 
milk  from  each  cow  from  the  milk  pail  into  the  cooler,  the  opening 
of  the  reagent  glass  is  kept  in  a  position  to  fill  the  glass. 

In  taking  samples  from  each  quarter,  it  is  advisable  to  milk 
the  secretion  of  each  quarter  in  a  cleanly  manner  into  the  reagent 
glass.  The  sample  is  taken  from  the  middle  milking,  that  is  after 
the  quarter  has  been  partially  milked.  All  samples  have  to  be 
accurately  marked  according  to  cow  and  quarter. 

In  protracted  examinations,  for  instance,  for  the  detection  of 
tubercle  bacilli,  it  is  recommended  to  divide  the  animals  of  large 
herds  into  groups,  and  to  collect  the  milk  from  each  five  or  ten 
cows  into  a  sample  bottle. 

For  the  determination  of  dirt  in  milk,  which  rapidly  sinks  to 
the  bottom,  it  is  recommended  to  take  an  average  sample  from  the 
well-mixed  milk,  and  allow  the  sediment  to  settle  in  a  separate 
container,  which  is  examined  after  the  milk  is  poured  off. 

After  arrival  at  the  laboratory,  the  samples  must  be  examined 
as  soon  as  possible ;  however,  until  the  examination,  they  must  be 
kept  in  the  ice-box  or  in  the  cooler. 

(b)  Examination  of  Milk. 

The  veterinarian  may  have  to  perform  the  preliminary  testing 
of  milk  as  to  adulterations,  but  he  will  especially  have  to  consider 
the  changes  in  milk  which  are  caused  by  animal  diseases,  inflamma- 
tion of  the  udder,  or  he  has  to  pass  judgment  on  possible  changes 
caused  by  certain  external  or  internal  influences.  A  final  opinion 


Adulteration.  213 


should  never  be  given,  except  after  a  most  intimate  knowledge  of 
the  special  conditions. 

Milk  mixed  from  many  cows  has  to  be  judged  differently  from 
milk  of  one  or  a  small  number  of  cows,  because  in  the  latter  case 
the  fluctuation  through  internal  or  external  influences  may  be  very 
marked,  whereas  the  presence  of  abnormal  secretions  from  one  or 
several  cows  is  either  modified  or  concealed  through  mixing  their 
milk  with  that  from  many  healthy  cows. 

An  adulteration  should  never  be  established  or  the  degree  of 
adulteration  calculated,  without  making  comparative  tests  of  satis- 
factory samples  from  the  same  source.  A  definite  diagnosis  of  the 
degree  of  adulteration  based  merely  on  the  values  of  accepted 
averages,  normal  or  experimental,  would  be  erroneous,  of  which 
no  scientific  milk  inspector  should  be  guilty. 

Before  the  beginning  of  the  examination,  each  sample  should 
be  sufficiently  mixed  by  shaking,  without  having  any  considerable 
amount  of  air  shaken  into  the  milk. 

The  testing  of  milk  is  divided  into  the  preliminary  examina- 
tion and  the  special  scientific  examination. 

Through  tests  by  means  of  the  senses  milk  is  first  examined 
as  to  the  color.  Adulterated  market  milk  is  often  bluish,  and 
secretions  from  animals  with  udder  diseases  often  make  the  milk 
reddish. 

The  odor  is  determined  either  immediately  after  emptying 
the  cans  or  in  the  laboratory  by  heating  the  milk  in  glass  beakers 
up  to  the  formation  of  steam.  The  odor  of  good  and  palatable 
market  milk  may  even  vary  considerably.  If,  however,  special 
odors  are  very  conspicuous,  the  presence  of  certain  milk  defects 
must  be  considered,  possibly  as  the  result  of  bacterial  action. 

The  consistence  of  the  milk  should  not  be  too  thin  or  watery, 
(suspicion  of  adulteration),  and  neither  should  it  be  sticky,  slimy, 
greasy  or  curdling,  which  changes  indicate  diseases,  particularly 
udder  affections,  or  the  presence  of  certain  bacteria  of  milk  which 
have  propagated  since  the  milk  was  secreted. 

A  fine  vesicular  foam  appearing  after  shaking  should  rapidly 
become  large  bubbles  and  disappear.  The  remaining  fine  vesicular 
foam  is  the  result  of  shaking  soapy  milk. 

The  taste  is  to  be  judged  in  the  same  manner  as  the  odor.  The 
milk  should  be  delivered  and  sold  in  a  cold  condition,  and  therefore 
in  the  collection  of  all  samples  of  milk  the  temperature  should  be 
ascertained. 

With  market  milk  the  positive  result  of  the  boiling  test,  that 
is  when  the  milk  curdles,  is  a  sign  of  advanced  decomposition  (10 
to  12  degrees  of  acidity  according  to  Henkel-Soxhlet). 

With  the  fresh  milk  of  individual  cows,  curdling  after  boiling 
indicates  inflammation  of  the  udder,  the  curdling  being  mostly 
limited  to  the  milk  of  individual  quarters  or  to  the  colostral  milk 
at  the  beginning  or  at  the  end  of  lactation. 


214  Milk   Inspection. 


The  alcohol  test  also  curdles  market  milk  which  has  become 
spoiled  (8  to  9  degrees  of  acidity). 

A  positive  reaction  with  fresh  samples  from  individual  cows 
or  with  samples  from  separate  quarters  indicates  either  a  physio- 
logical or  severe  pathological  inflammatory  condition  of  the  milk 
glands.  The  milk  is  mixed  with  an  equal  amount  of  68%  alcohol. 

Recently,  the  alizarol  test  has  been  recommended  for  the  de- 
termination of  spoiled  milk.  Milk  mixed  with  an  equal  part  of 
alizarol  becomes  brownish  violet,  as  long  as  it  is  fresh  and  not 
spoiled ;  otherwise  the  color  turns  brown  and  yellow,  and  the  milk 
curdles,  with  the  formation  of  thick  flakes. 

For  the  control  of  market  milk  or  for  the  diagnosis  of  udder 
diseases  the  author  found  that  the  alizarol  test  (milk  with  68% 
alcohol  and  as  much  alizarin  as  is  soluble)  is  without  any  value  in 
testing  samples  of  individual  cows  or  quarters. 

The  degree  of  acidity  of  the  milk  is  established  by  titration 
with  standard  alkali. 

1.  According  to  Henkel-Soxhlet,  with  y±  normal  sodium  hy- 
drate solution,  fresh  market  milk  has  about  6.0  degree  of  acidity. 

2.  According  to  Thorner  and  Pfeifer,  with  TO   normal  so- 
dium hydrate  solution  in  10  c.  c.  of  milk  and  20  or  40  c.  c.  of  water, 
respectively,  with  5  drops  of  a  2%  solution  of  phenolphthalein 
(the  figures  thus  obtained  are  multiplied  by  10)  fresh  milk  has 
about  18  degrees  of  acidity. 

According  to  Henkel-Soxhlet,  the  acidity  is  determined  by 
titrating  50  c.  c.  of  milk,  to  which  2  c.  c.  of  a  2%  alcoholic  solution 
of  phenolphthalein  have  been  added,  to  a  faint  but  permanent 
pink.  Each  y2  c.  c.  of  alkali  (i/4  normal  sodium  hydrate)  corre- 
sponds to  a  degree  of  acidity. 

Schern  utilizes  10  c.  c.  of  milk  and  titrates  drop  by  drop  with 
1/40  normal  sodium  hydrate  solution  after  having  added  1  to  2 
drops  of  the  solution  of  phenolphthalein.  The  titration  takes  place 
in  a  mixing  cylinder  which  is  so  graduated  that  the  difference  of 
the  level  of  the  fluid  before  and  after  the  titration  shows  the  degree 
of  acidity. 

An  increased  degree  of  acidity  in  market  milk,  for  instance, 
7  or  more  after  the  method  of  Henkel-Soxhlet,  does  not  always 
indicate  a  spoiled  condition.  This  can  only  be  presumed  when  the 
increase  of  acidity  in  a  certain  time  and  at  a  certain  temperature 
is  very  rapid,  in  other  words,  when  the  curve  of  acidity  is  abrupt. 
After  12  to  24  hours  the  degree  of  acidity  is  again  determined. 
Fresh  milk,  kept  at  20  degrees  C.,  shows  from  10  to  15  to  20  de- 
grees of  acidity  after  24  hours.  Milk  at  the  end  of  the  incubation 
period,  before  bacterial  multiplication  begins,  has  25  to  30  degrees 
of  acidity,  and  old  milk  30  to  40  degrees.  The  increase  in  degrees 
of  acidity  between  fresh  milk  and  older  milk  is  caused  by  the  for- 
mation of  lactic  acid.  One  c.  c.  of  !/4  normal  sodium  hydrate— 22 . 5 
mg.  lactic  acid,  and  1  c.  c.  of  iV  normal  sodium  hydrate=9  mg. 


Hoyberg's    Test.  215 


lactic  acid.  In  spite  of  this,  the  degrees  of  acidity  of  Henkel- 
Soxhlet  cannot  be  computed  into  the  degrees  of  acidity  of  Pfeifer 
because  through  dilution  with  water  the  solution  of  slightly  soluble 
phosphates  decreases  the  degrees  of  acidity  obtained,  and,  there- 
fore, the  degrees  of  acidity  of  Thorner  and  Pfeifer  show  lower 
values  than  those  of  Henkel-Soxhlet. 

Milk  from  individual  cows  often  have  greatly  decreased  or 
increased  degrees  of  acidity.  The  decreased,  or,  more  rarely,  in- 
creased degree  of  acidity  of  a  single  sample  creates  the  suspicion 
that  the  cow  is  suffering  from  udder  disease.  High  acidity  of  all 
four  quarters  is  present  with  colostrum  and  in  milk  of  fresh  cows. 
The  milk  from  cows  at  later  periods  of  lactation  is  frequently 
alkaline  and  has  a  lower  degree  of  acidity. 

Dropped  on  litmus  paper,  market  milk  shows  an  amphoteric 
reaction.  Alkaline  reactions  of  single  samples  must  be  judged 
the  same  as  low  degrees  of  acidity.  If  market  milk  shows  an  alka- 
line reaction,  an  alkali  may  have  been  added  for  preservation. 
The  reaction  of  market  milk  is  acid  to  rosolic  acid.  On  the  addi- 
tion of  alkali  to  milk,  the  milk,  upon  adding  rosolic  acid-alcohol, 
turns  rose  red.  With  fresh  single  samples  of  milk  the  red  color 
after  the  addition  of  rosolic  acid-alcohol  is  an  indication  of  the 
presence  of  inflammation  of  the  udder;  cows  in  the  late  periods 
of  lactation  may  also  show  red  coloring  of  the  milk. 

To  lacmoid  the  milk  is  alkaline,  and  also  to  dimethyl  orange. 
The  so-called  Hoyberg  test  to  determine  "fibrin  and  pus"  in 
samples  of  milk  from  individual  cows  is  based  on  the  difference 
in  the  reaction  of  the  milk. 

The  test  is  conducted  so  that  5  c.  c.  milk  (individual  cows  or 
quarters)  are  mixed  with  5.5  c.  c.  solution  of  rosolic  acid,  which 
is  prepared  from  0.45  c.  c.  of  a  1%  solution  5  c.  c.  plus  alcohol. 

A  positive  reaction  to  the  test  creates  suspicion  while  a  nega- 
tive result  does  not  exclude  it. 

As  the  reaction  of  milk  from  diseased  quarters  frequently  is 
perfectly  normal  or  acid,  the  test  does  not  compare  with  the 
Trommsdorff  test,  and  especially  the  microscopical  examination. 
Besides,  it  is  very  difficult  to  distinguish  the  fine  differences  in  the 
color  shades. 

The  determination  of  the  alkalinity  of  milk  with  -fa  normal 
acid  has  so  far  not  been  adopted  in  practice. 

The  dirt  content  of  milk  should  not  be  weighed,  as  recom- 
mended by  Renk,  since  the  amount  of  visible  foreign  material 
should  not  determine  the  disposition,  but  rather  its  quality 
should  be  considered.  Besides,  much  dirt  is  dissolved  in  the  milk, 
which  neither  can  be  determined  through  filtration  nor  through 
weighing  the  filters.  The  amount  of  dirt  is  estimated  in  degrees, 
through  the  sedimentation  method  or  through  filtration,  and  the 
quality  is  thus  determined;  as  a  rule  it  represents  remnants  of 
feed,  feed  dust,  portions  of  litter,  manure  of  cows,  cow  hairs,  etc. 


21 6  Milk   Inspection. 


From  the  uniformly  fine  or  coarse  particles  of  dirt  in  milk,  or 
from  the  presence  of  cow  hair  in  large  amounts  and  larger  par- 
ticles of  dirt,  it  may  be  determined  whether  the  dirty  milk  has 
been  strained  after  the  milking. 

The  filtration  methods  in  which  disks  of  cotton  are  used  as 
filters  have  an  advantage  in  that  they  indicate  more  distinctly  the 
actual  content  of  dirt  than  the  sedimentation  methods,  where  a 
considerable  proportion  of  the  dirt  is  drawn  up  into  the  cream 
during  the  separation.  The  author  uses  an  apparatus  in  which  a 
disk  of  cotton  is  held  in  a  simple  plate-shaped  filter,  over  the  vessel 
into  which  the  milk  is  to  be  poured.  The  cotton  disk  is  pressed 
into  the  filter  by  a  glass  cylinder,  as  is  the  case  with  the  apparatus 
of  Fliegel  and  Bernstein.  At  the  present  time  such  dirt  testing 
apparatus  may  be  purchased  from  nearly  all  dealers.  For  the 
household  and  for  small  amounts  of  milk  certain  filters  are  recom- 
mended like  those  in  which  the  filling  funnel  represents  a  bottom- 
less bottle,  to  the  mouth  of  which  a  ring  and  a  wire  strainer  con- 
taining a  disk  of  cotton  are  attached,  by  means  of  a  wire  fastener. 

Henkel's  control  filter  is  also  based  on  the  principle  of  filtra- 
tion through  cotton  by  which  an  angle-shaped  segment  of  the  filter- 
ing disk  remains  free  from  dirt  in  order  to  control  the  purity  of 
the  milk.  The  same  result  is  attained  with  other  methods  where 
the  border  of  the  filtering  disk  remains  free  from  dirt. 

At  the  places  of  official  examination  of  milk  distinction  is 
made  between  slight,  moderate,  strong,  very  strong,  and  exception- 
ally strong  pollution,  and  the  milk  accordingly  is  judged  as  either 
clean  or  spoiled  or  even  injurious  to  health. 

Market  milk  may  be  tested  at  receiving  stations  either  by 
drawing  up  samples  from  the  bottom  of  the  cans  with  the  aid  of 
long  pipettes,  or,  as  is  customary  in  Munich,  by  pouring  the  milk 
from  the  original  can  into  another  vessel.  The  residue  of  the  milk 
in  the  first  case  is  taken  as  a  sediment  sample,  while  an  average 
sample  is  taken  from  the  mixed  milk  of  the  second  container  in 
order  to  make  a  quantitative  estimation. 

Trommsdorff's  test  is  splendidly  adapted  to  the  detection  of 
finely  divided  particles  of  dirt,  the  heavy  particles  being  collected 
in  a  capillary  tube. 

The  methylene  blue  reductase  test  gives  very  good  information 
relative  to  bacterial  multiplication.  A  solution  of  methylene  blue 
in  water,  serves  as  a  reagent,  consisting  of  195  parts  H20  and  5 
parts  saturated  alcoholic  methylene  blue  solution.  The  test  is  con- 
ducted by  placing  20  c.  c.  of  milk  and  1  c.  c.  of  methylene  blue 
solution  in  a  reagent  glass  at  40°  C.  and  the  time  is  determined  in 
which  the  sky  blue  mixture  becomes  completely  white.  Milk  which 
becomes  white  in  less  than  3  hours  is  already  old.  The  age,  how- 
ever, does  not  refer  to  the  hours  since  its  production,  but  means  that 
the  milk  has  "aged."  Milk  which  is  obtained  in  a  dirty  condition, 


Reductase   Test.  217 


lias  not  been  cooled,  and  has  been  transported  in  poorly  cleaned 
cans,  ages  more  rapidly  than  milk  which  has  been  properly  treated. 

In  making  the  test  it  is  not  necessary  to  cover  the  sample  in 
the  reagent  glass  with  boiled  oil  or  kerosene  since  there  is  no 
advantage  in  such  a  procedure.  In  the  same  way  the  "reductase" 
which  is  recommended  by  commercial  firms  is  of  no  advantage. 

Fresh  milk  from  individual  cows  may  be  rapidly  reduced 
owing  to  the  large  content  of  cells. 

Very  valuable  results  are  obtained  with  the  reductase  test 
when  conducted  in  connection  with  the  microscopic  examination  of 
the  sediment. 

Frequently,  in  the  testing  of  the  centrifugal  sediment,  large 
numbers  of  bacteria  are  found  not  infrequently  agglutinated  in 
colonies,  and  the  milk,  in  spite  of  the  apparently  high  content  of 
bacteria,  has  very  little  reducing  power.  This  is  an  indication 
that  the  milk  has  been  transported  in  uncleaned  cans,  but  does 
not  in  itself  prove  decomposition. 

Microscopically  in  the  residue  of  milk  in  the  can  are  found 
milk  souring  bacteria,  diplococci,  streptococci,  sarcines,  besides 
oidia,  coli,  and  rods. 

Such  is  also  the  case  when  the  milk  is  obtained  under  dirty  con- 
ditions, but  is  promptly  delivered. 

The  author  determines  the  reduction  property  of  the  milk  in 
the  following  manner : 

For  each  sample  of  milk  10  small  tubes  are  used  containing 
1,  2,  3,  4,  up  to  10  drops  of  methylene  blue  solution,  respectively. 
Into  each  tube  5  c.  c.  of  milk  is  added.  After  14,  %,  1,  2  hours, 
etc.,  observations  are  made  as  to  what  extent  the  milk  has  been 
reduced.  This  method,  in  spite  of  its  apparently  greater  technique 
is  nevertheless  quite  simple,  as  the  constant  watching  of  the  sam- 
ples in  order  to  determine  the  time  is  unnecessary.  Both  time  and 
degree  are  determined.  If,  for  instance,  a  milk  is  reduced  in  three 
hours  to  tube  8,  then  the  formula  will  be:  R3— 8.  Good  milk 
reduces  the  first  2  tubes  only  after  2  to  3  hours;  fresh  milk  only 
after  10  to  12  hours. 

The  Schardinger  reduction  of  formalin  methylene  blue  is  of 
no  value  for  the  examination  of  market  milk,  as  it  also  gives  posi- 
tive results  with  fresh,  raw,  and  boiled  spoiled  milk.  In  the  same 
way  it  is  not  suited  for  examination  of  milk  from  individual  cows. 
Milk,  which  does  not  decolorize  in  a  few  minutes  at  60°  C.  by  the 
Schardinger  reagent,  consisting  of  190  parts  water,  5  parts  forma- 
lin and  5  parts  saturated  alcoholic  methylene  blue  solution,  may 
be  from  fresh  cows,  if  the  individual  sample  is  taken  from  the  total 
amount  of  milk  of  the  cow  (the  first  portion  of  milk  at  the  milking 
does  not  reduce). 

The  "Catalase"  test  is  conducted  by  mixing  together  15 
c.  c.  of  milk  and  5  c.  c.  of  \%  peroxide  of  hydrogen.  The  mixture 
is  placed  in  a  fermentation  tube  such  as  is  used  in  the  examination 


218  Milk   Inspection. 


of  wine  for  the  determination  of  sugar,  and  kept  for  2  hours  in 
an  incubator,  and  after  this  period  the  amount  of  oxygen  formed 
during  this  time  is  measured.  It  should  not  exceed  more  than 
about  1  c.  c. 

Apparatuses  which  indicate  the  total  amount  of  gas  formed 
are  more  suitable;  for  instance,  the  "Catalaser"  constructed  by 
Henkel,  or  still  better  the  one  by  Lobeck,  in  which  a  gas  collecting 
and  measuring  tube  is  so  attached  above  the  bulb  containing  the 
milk  that  a  fine  gas  tube  leading  from  the  bulb  to  the  upper  part 
of  the  gas  measuring  apparatus  allows  the  exit  of  the  oxygen  at  the 
0  point.  At  the  bottom  of  the  gas  collecting  tube  another  tube 
opens,  through  which  the  water  contained  in  the  measuring  tube 
is  displaced  by  the  liberated  oxygen.  Faitelowitz  has  constructed 
a  shaking  apparatus  and  a  special  "Catalaser";  the  shaking  is 
supposed  to  expedite  the  liberation  of  the  oxygen. 

Fresh  milk  evolves  1  to  2  c.  c.  of  oxygen.  Eaw  or  pasteurized 
milk,  spoiled  through  invasion  of  bacteria,  produces  considerably 
larger  amounts  of  oxygen;  likewise  milk  rich  in  cellular  elements 
as  a  result  of  physiological  or  pathological  irritations  of  the  udder, 
or  mixed  milk  polluted  by  such  secretions.  The  test  is  useless  for 
the  examination  of  market  milk  as  to  the  presence  of  inflammations 
of  the  udder. 

High  oxygen  values  of  the  catalase  test  in  connection  with  low 
reductase  values  against  the  watery  methylene  blue,  create  a  sus- 
picion of  mastitis. 

High  values  by  both  methods  indicate  principally  a  spoiled 
condition,  without  differential  diagnostic  value  relative  to  inflam- 
mation of  the  udder  or  bacterial  decomposition.  If  the  testing  of 
the  milk  indicates  that  the  product  was  pasteurized,  sterilized  or 
otherwise  heated,  and  the  catalase  test  is  positive,  the  generation 
of  oxygen  proves  the  spoiled  condition  of  the  milk  as  a  result  of 
bacterial  decomposition. 

With  fresh  individual  samples  and  samples  from  individual 
quarters  the  increased  value  of  catalase  proves  the  presence  of 
mastitis,  provided  that  no  severe  general  diseases  are  present,  and 
provided  physiological  irritating  conditions  are  excluded.  If  all 
samples  from  the  4  quarters  show  increased  catalase  values,  mas- 
titis may  be  present  in  all  4  quarters,  or  there  may  exist  a  general 
disease,  as  for  instance  tuberculosis  or  peritonitis. 

The  test  for  amylase  is  only  applicable  to  raw  milk.  Into  each 
of  ten  test  tubes  are  placed  10  c.  c.  of  milk  and  0 . 1,  0 . 2  up  to  1  c.  c. 
of  a  1%  solution  of  soluble  starch  which  is  dissolved  through  heat- 
ing. The  series  of  tubes  are  placed  for  half  an  hour  in  the  incu- 
bator. Then  they  are  rapidly  cooled,  and  to  each  is  added  1  c.  c.  of 
a  solution  of  iodine  and  iodide  of  potassium  (1  of  iodine,  2  of  iodide 
of  potassium,  300  of  water).  If  the  total  amount  of  starch  has 
been  converted  into  sugar,  the  color  of  the  mixture  will  be  yellow. 
A  grayish-yellow  with  a  grayish-blue  tinge  indicates  unchanged 


Fermentation    Test.  219 


residues  of  starch.     Generally  only  tubes  1  and  2  but  sometimes 
tube  3  become  yellow. 

In  the  presence  of  large  amounts  of  amylase,  which  usually 
runs  parallel  with  the  cellular  contents,  even  the  other  tubes  will 
appear  yellow.  An  increased  amount  of  amylase  indicates  physio- 
logical or  pathological  irritation  of  the  udder.  The  raw  condition 
of  the  milk  is  tested  by  the  determination  of  peroxydase.  There 
are  used  either  guaiac  tinctures,  the  efficacy  of  which  has  been 
tested,  or  still  better  mixtures  of  guaiac-guaiacol  with  peroxide  of 
hydrogen,  for  instance,  resina  guaiaci  10.0,  guaiacol  10.0,  3% 
perhydrol  quantum  satis,  absolute  alcohol  80.0  (Schern). 

Raw  milk  becomes  blue,  heated  milk  turns  yellow.  The  Roth- 
enfuss  reagent  is  very  reliable  and  is  also  recommended  on  account 
of  its  keeping  qualities. 

First  solution :  1  gm.  paraphenylendiamin  hydrochloride,  15 
c.  c.  water. 

Second  solution:  2  gm.  crystallized  guaiacol,  135  c.  c.  96% 
alcohol. 

After  dissolving,  both  are  mixed  together  which  results  in  a 
white  or  whitish-yellow  reagent.  For  the  execution  of  the  test  a 
0.2%  solution  of  peroxide  of  hydrogen  is  also  essential.  The  milk 
to  be  tested  is  mixed  with  a  few  drops  of  a  solution  of  peroxide  of 
hydrogen,  and  then  the  reagent  is  added.  Eaw  milk  at  once  be- 
comes intensely  violet,  while  milk  heated  to  over  80°  C.  remains 
white. 

The  reaction  is  prettier  and  more  distinct  when  instead  of 
milk,  milk  serum  is  used,  which  is  prepared  in  the  following 
manner : 

100  c.  c.  of  milk  is  mixed  with  6  to  12  c.  c.  of  lead  acetate 
solution,  strongly  shaken,  and  filtered  through  a  folded  filter.  At 
the  plane  of  contact  of  the  serum  with  the  reagent,  a  violet  ring 
appears  if  the  milk  is  raw. 

If  the  reaction  does  not  appear,  and  the  lead-acetate-serum 
becomes  turbid  through  boiling,  the  milk  has  been  heated  above 
80°  C.  and  probably  below  the  boiling  temperature,  which  however 
was  surely  reached  when  on  boiling  of  the  serum  no  more  albumen 
is  precipitated. 

The  fermentation  test  has  less  importance  for  the  examination 
of  milk  to  be  consumed  than  of  milk  to  be  utilized  for  the  manu- 
facture of  cheese. 

The  milk  is  filled  into  tall,  wide  test  tubes  and  the  latter  are 
placed  for  24  hours  in  the  incubator  at  38-40°  C. 

Fresh  milk  does  not  curdle  after  12  hours ;  curdled  milk  should 
have  a  pure  sour  odor  and  taste,  and  at  the  same  time  a  porcelain- 
like,  scaly,  coagulum  with  only  a  few  gas  bubbles.  Many  gas  bubbles 
and  fissures  in  the  coagulum  indicate  the  presence  of  aerogenes-coli 
and  other  bacteria  which  split  up  the  milk  sugar  with  the  forma- 
tion of  gas.  A  cheese-like  curd  develops  as  a  result  of  the  presence 


220  Milk   Inspection. 


of  rennet  producing  species-  of  bacteria,  which  are  peptonizing 
bacteria,  the  presence  of  which  is  undesirable  in  drinking  milk. 
Not  infrequently  the  best  milk  produces  imperfect  curds. 

Milk  from  diseased  animals  curdles  more  poorly,  with  the 
formation  of  an  abnormal  curd. 

Still  less  important  than  the  fermentation  test  is  the  rennet 
fermentation  test  which  is  used  in  cheese  factories,  where  the 
milk,  before  being  placed  in  the  incubator  is  mixed  with  a  solution 
of  rennet.  The  resulting  curd  should  be  elongated  and  worm- 
shaped,  contain  few  gas  bubbles,  and  should  not  look  twisted  or 
pressed  flat  or  swollen. 

The  rennet  inhibitory  test  recently  recommended  by  Schern 
accomplishes  other  purposes  than  the  rennet  fermentation  test.  It 
tests  the  power  of  resistance  of  the  milk  against  the  effect  of  the 
rennet.  For  the  test  the  following  are  necessary : 

1.  A  number  of  test  tubes. 

2.  Measuring  pipettes  of  10  c.  c.  capacity  with  y2  c-  c-  gradua- 
tion and  1  c.  c.  pipettes  divided  in  tenths  and  hundredths  of 
c.  c.  graduations. 

3.  A  water  bath  or  an  incubator  with  a  number  of  perforated 
racks. 

4.  An  icebox. 

5.  0.85%  solution  of  common  salt. 

6.  Solutions  of  rennet,  the  values  of  which  are  known  and 
which  remain  constant  (standard  solutions  of  a  known  titer). 

In  the  performance  of  the  test  it  is  desired  to  ascertain : 

1.  Whether  the  titer  of  the  solution  of  rennet  still  persists 
with  sound  milk. 

2.  Whether  the  milk  to  be  tested  by  means  of  the  rennet 
titer  does  not  curdle,  or  how  much  more  rennet  is  necessary  to 
make  the  milk  curdle. 

The  samples  are  placed  for  1  hour  in  the  icebox,  and  then  for 
2  hours  in  the  incubator,  whereupon  through  pouring,  a  test  is 
made  as  to  which  dilution  of  rennet  has  curdled  the  milk  or 
whether  the  milk  curdles  at  all  up  to  the  limit  of  titration. 

The  test  is  not  applicable  to  market  milk,  but  only  for  fresh 
individual  samples  or  samples  of  milk  from  individual  quarters. 

Milk  which  utilizes  considerably  more  of  the  rennet  solution 
than  the  amount  which  corresponds  with  its  titer  is  suspected  of 
not  being  normal. 

The  test  is  too  laborious  for  practical  control  work  and  does 
not  offer  any  advantages  for  the  recognition  of  inflammation  of 
the  udder  over  the  microscopical  examination  of  the  centrifugal 
sediment. 

The  methods  by  which  the  milk  is  examined  for  the  content  of 
complement  or  amboceptor  have  the  same  shortcomings.  They 
are  of  no  importance  in  control  work. 

The  test  for  complement  is  as  follows: 


Sedimentation   Test. 


1.  5%  suspension  of  washed  blood  corpuscles  from  guinea 
pigs  or  rabbits  in  0.85%  salt  solution. 

2.  Hemolytic  amboceptor  of  normal  blood  from  cattle   or 
goats  heated  to  56°  C. 

3.  Milk. 

The  milk  is  placed  in  tubes  arranged  in  2  rows  of  5  tubes 
each  in  quantities  of  1.0,  0.5,  0.25,  0.1  and  0.0  c.  c.  respectively. 
One  row  is  inactivated  by  heating  to  56°  C. ;  then  in  all  the  tubes 
the  contents  are  brought  up  to  1  c.  c.  by  adding  salt  solution.  Fur- 
ther, to  each  tube  are  added  0.2  c.  c.  of  the  inactivated  cattle  or 
goat  serum- and  0.5  or  1  c.  c.  of  the  blood-cell  suspension.  The 
rack  is  then  placed  for  2  hours  in  the  incubator  (shaken  frequent- 
ly) and  placed  over  night  in  the  icebox. 

Hemolysis  occurs  in  physiological  and  pathological  irritations 
of  the  udder. 

The  test  for  amboceptors  is  carried  out  in  a  similar  manner, 
with  the  exception  that  the  milk  in  all  the  tubes  is  inactivated,  and 
into  the  tubes  of  one  row  complement  is  added  in  quantities  deter- 
mined by  titration. 

In  the  test  for  amboceptor  and  complement  the  various  sub- 
stances which  enter  into  the  test  should  be  controlled  for  possible 
errors. 

Trommsdorff's  method  is  best  adapted  to  determining  the 
quantity  of  centrifugal  sediment  in  milk. 

The  tubes  which  terminate  at  the  bottom  in  a  graduated  capil- 
lary tube  (Trommsdorff's  tubes)  are  filled  with  10  c.  c.  of  milk 
and  centrifugalized  for  several  minutes  in  a  centrifuge  at  about 
1500  to  2000  revolutions  per  minute.  All  elements  having  the 
greatest  specific  gravity  collect  in  the  capillary  tube. 

All  sediment  of  a  yellow,  clay  or  reddish  color  which  does  not 
consist  of  cow  manure  and  which  is  sharply  separated  from  the 
layer  of  skimmed  milk  irrespective  of  its  quantity,  should  be  sus- 
pected as  being  due  to  an  inflammation  of  the  udder,  since  larger 
quantities  of  tissue  cells  are  thrown  off  only  in  pathological  or 
physiological  irritations  of  the  udder.  In  market  milk  this  test 
gives  uncertain  results,  but  in  individual  samples  and  in  samples 
of  individual  quarters  the  results  may  be  well  utilized.  If  the 
centrifugalized  sediment  is  not  distinctly  separated  from  the 
skimmed  milk,  and  the  scale  is  therefore  not  readable,  then  the  tube 
is  filled  with  clear,  cool  water  and  the  capillary  end  is  turned  up- 
ward. The  water  having  a  lower  specific  gravity,  penetrates  into 
the  capillary  tube  up  to  the  border  of  the  sediment. 

For  testing  of  individual  quarters  the  author  recommends  the 
sedimentation  test  in  tubes  with  chisel  shaped  ends  and  with 
funnel  shaped  mouths.  The  milk  is  drawn  directly  into  these  tubes 
from  the  quarter,  after  discarding  the  first  milk.  The  four  sam- 
ples from  a  cow  are  allowed  to  stand  for  about  8  hours  and  then 


222  Milk   Inspection. 


examined  for  the  presence  of  sediment.  Sediment,  which  appar- 
ently does  not  consist  of  cow  manure,  indicates  an  inflammation  of 
the  udder,  provided  the  colostral  stage  has  passed  and  the  animal 
is  not  close  to  the  end  of  its  lactation  period. 

The  sedimentation  test  may  be  and  should  be  undertaken  by 
every  dairyman.  Its  application  is  easy.  Milk  which  separates 
recognizable  quantities  of  sediment  should  not  be  sold  or  used  as 
food  for  man. 

In  the  scientific  examination  of  market  milk  and  of  individual 
samples,  the  microscopical  study  of  the  milk  can  no  longer  be 
neglected.  In  Munich  the  sediment  of  the  milk  is  examined  micro- 
scopically. A  platinum-wire  loop  (the  wire  must  be  completely 
folded)  is  passed  into  the  depth  of  the  capillary  tubes  and  without 
turning,  the  sediment  is  lifted  out  by  pressing  the  wire  against  one 
side  and  drawing  out  a  loopful.  In  the  procedure  the  contact  of 
the  wire  with  the  milk  or  cream  of  the  tube  should  be  prevented. 
The  smear  is  made  in  the  usual  manner ;  the  best  way  is  to  place 
the  loop  of  the  wire  on  the  slide  and  by  lifting  it  up  a  somewhat 
thicker  droplet  remains  at  the  place  of  contact.  This  may  be 
spread  over  the  slide  and  is  especially  well  adapted  for  microscop- 
ical examination. 

The  smear  is  dried  in  the  air,  fixed  by  heat  or  alcohol  and 
stained  by  the  ordinary  methods.  For  staining,  the  author  recom- 
mends a  thionin  solution  which  consists  of  y$  concentrated  alco- 
holic thionin  solution  and  2/z  distilled  water.  In  market  milk  are 
observed  many  plant  fibers  and  plant  cells,  plant  hairs,  staphylo- 
cocci  united  into  colonies,  colon  varieties,  acid  fast  rods,  sarcina, 
blackleg  and  anthrax-like  bacteria  with  or  without  spores,  if  the 
milk  was  produced  under  dirty  conditions.  If  such  a  milk  sample 
is  older,  not  infrequently  mycelial  threads  germinate  from  the 
mould  spores.  If  the  milk  is  bad  and  was  transported  in  dirty 
cans,  besides  the  colon-like  bacteria,  staphylococci,  diplococci, 
streptococci,  sarcina,  oidia  and  cheese  bacteria  may  be  seen. 

If  the  milk  is  at  the  point  of  decomposition,  diplococci  and 
streptococci  dominate  the  field. 

A  diagnosis  that  milk  is  mixed  with  the  secretion  of  a  cow 
affected  with  streptococcic  mastitis  is  only  permissible,  when 
besides  the  cells  from  the  animal  body  (leucocytes,  epithelia  under- 
going fatty  degeneration,  erythocytes,  etc.),  the  animal  forms  of 
streptococci  are  demonstrated. 

The  positive  finding  is  decisive  but  the  negative  does  not 
exclude.  Market  milk  which,  besides  numerous  leucocytes,  shows 
no  animal  streptococci,  only  creates  a  suspicion  that  the  secretion 
is  from  cows  with  affected  udders. 

The  increased  amount  of  horny  epithelia  of  the  teats  in  sam- 
ples of  individual  cows  indicates  the  fresh  milking  period  of  the 
animal. 


Table  V. 


Sediment  of  dirty  market   milk    which    contains  the    secretions  of    cows  with  affected 
udders,  and  which  has  been  transported  in  filthy  cans.     Thionin  stain.      1  X  1000. 


Ernst,  Milk  Hygiene. 


Microscopic    Examination.  223 


The  presence  of  epithelial  nests  from  the  cistern  suggests  a 
catarrh  of  the  cistern. 

An  increased  number  of  leucocytes  and  colostral  cells  indicates 
an  irritation  of  the  parenchyma.  The  causes  of  the  irritations 
are  often  manifested  by  the  presence  of  diplococci  in  phagocytes 
or  isolated  diplococci  and  frequently  atypical  short  forms,  or  the 
typical  animal  forms  of  the  Streptococcus  longus  or  S.  brevis  are 
recognized. 

Even  atypical  forms  of  diplococci  and  streptococci,  when  pres- 
ent in  such  forms  in  milk  only  a  few  hours  old,  are  an  indication  of 
streptococcic  mastitis  (care  must  be  exercised  in  the  absence  of 
experience  and  if  the  evidence  is  to  be  used  in  court). 

In  pyobacillosis  the  typical,  short,  slender  bacilli  are  found 
which  simulate  in  their  morphology  the  bacilli  which  frequently 
cover  the  horny  cells  of  the  outside  skin  of  the  teats. 

In  samples  from  individual  cows,  the  microscopical  examina- 
tion may  establish  the  diagnosis  of  "tuberculosis  of  the  udder," 
when  the  specific  organisms  are  found  enclosed  in  leucocytes  or 
curds.  The  staining  is  carried  out  with  hot  carbol-fuchsin  solution 
(1  part  fuchsin  to  10  parts  of  absolute  alcohol,  and  90  parts  of  a 
5%  carbolic  acid  solution).  By  decolorizing  with  33%  aqueous 
nitric  acid  and  subsequent  washing  with  alcohol  the  non-acid  fast 
rods  and  the  body  cells  are  decolorized.  The  decolorized  elements 
may  be  given  a  blue  contrast  stain,  against  the  red  tubercle  bacilli 
by  subsequent  staining  of  the  preparation  with  aqueous  methylene 
blue  or  methylene  blue  anilin  water. 

In  order  to  avoid  the  dragging  of  too  many  tubercle  bacilli 
into  the  cream  by  the  cells  and  fat  globules,  for  the  microscopical 
examinations,  the  milk  should  be  first  homogenized.  The  following 
methods  are  the  simplest : 

a.  Knut  Arnell  recommends  mixing  25  c.  c.  of  milk  with  2  c.  c. 
of  concentrated  ammonia  and  100  c.  c.  of  a  mixture  of  equal  parts 
of  ether  and  petroleum  ether  in  a  sedimentation  cylinder,  which 
runs  to  a  point  at  the  bottom  and  at  its  lower  part  is  supplied  with 
a  stopcock.     This  is  frequently  shaken  and  then  allowed  to  stand 
for  the  separation.     The  ammonia-casein  solution  is  then  drawn 
off,  the  remaining  content  is  centrifugalized  and  the  sediment 
examined. 

b.  Thorner  recommends  mixing  20  c.  c.  of  milk  with  1  c.  c.  of 
50%  potassium  hydrate.    This  is  heated  in  boiling  water  until  in 
complete  solution  and  then  centrifugalized. 

c.  Biedert  recommends  adding  10  c.  c.  of  milk  to  1000  c.  c.  of 
water  containing  4  to  8  drops  of  sodium  hydrate  solution.     This 
is  shaken,  boiled  and  then  set  away  for  sedimentation. 

If  after  staining,  the  slender  rods  which  remain  red  are  pres- 
ent only  in  small  numbers,  or  if  the  sediment  shows  no  cells  which 
indicate  an  inflammation  of  the  udder,  or  if  the  examined  milk 
proves  to  be  a  dirty  market  milk,  then  the  diagnosis  must  be  estab- 


224  Milk   Inspection. 


lished  by  incubation,  since  the  milk  may  contain  from  the  feed,  etc., 
only  harmless,  acid  fast  rods. 

The  inoculation  is  made  into  guinea  pigs  by  injecting  them 
either  subcutaneously  or  intramuscularly  in  the  hind  leg  with  either 
1  c.  c.  of  the  full  milk,  or  better,  with  the  centrifugal  sediment  mixed 
with  a  small  amount  of  the  skimmed  milk  with  or  without  cream. 
The  sediment  should  be  obtained  by  using  rapidly  revolving  elec- 
tric centrifuges. 

If  the  samples  have  to  be  transported  long  distances,  they 
should  be  mixed  before  transportation,  and  if  possible  immediately 
after  drawing  the  milk,  with  1:2000  to  1:3000  of  formalin  (boric 
acid  1 :50  or  1 :100  is  also  satisfactory).  The  tubercle  bacilli  wliich 
are  protected  by  a  waxy  capsule  from  the  effects  of  the  preserving- 
agents,  are  not  harmed  by  such  preservation  to  such  an  extent  that 
they  could  no  longer  be  demonstrated  by  inoculations. 

For  each  milk  injection  at  least  two  guinea  pigs  should  be 
used,  since  occasionally  the  inoculated  animals  die  as  a  result  of 
some  other  intercurrent  disease. 

In  the  presence  of  tubercle  bacilli  the  regional  lymph  glands 
swell  after  several  days  or  a  few  weeks.  Such  animals, 
if  they  do  not  die  before,  should  be  killed  on  the  appearance  of 
these  swellings,  and  they  as  well  as  those  which  died  should  be 
examined  for  the  presence  of  tuberculosis.  The  surviving  guinea 
pigs  should  be  kept  under  observation  for  several  months. 

In  examining  entire  herds,  it  is  advisable  to  group  the  cows ; 
for  instance,  five  animals  may  form  one  group  and  the  mixed  milk 
of  this  group  should  be  separately  inoculated. 

The  counting  of  bacteria  is  carried  out  either  by  the  ordinary 
method  of  plating  which  is  made  with  certain  dilutions  of  milk  on 
agar  or  gelatin  or  also  by  direct  counting  in  smears  which  should 
be  prepared  according  to  Olav  Skar. 

The  method  consists  in  mixing  in  a  reagent  glass  4/10  c.  c.  of  a 
2%  solution  of  carbol-methylene  blue  (for  animal  cells  and  bac- 
teria) and  3.5  c.  c.  carbol-methylene  blue,  with  0.5  c.  c.  of  a  3% 
sodium  hydrate  solution  (for  bacteria  alone).  Then  10  c.  c.  of  milk 
is  added  to  the  stain  with  a  pipette  and  heated  for  about  10  minutes 
at  70°  C.  Of  the  mixture,  1/50  of  a  c.  c.  is  uniformly  smeared 
upon  a  certain  sized  field  (24  X  20  m.  m.)  of  a  special  slide,  and 
dried  in  the  air.  Without  any  further  fixation  or  other  treatment,  a 
number  of  fields  in  the  smear  are  counted  in  their  entire  length  and 
width,  and  with  the  aid  of  the  ocular  micrometer  the  number  of 
bacteria  in  the  counted  fields  is  calculated  to  the  c.  c.  of  milk,  ac- 
cording to  the  standard  given  below.  When  chains  and  clumps  are 
encountered  each  bacillus  must  be  counted.  The  ocular  micrometer 
of  Zeiss  in  Jena  as  applied  by  Skar  has  a  determined  field  capacity 
so  that  one  bacterium,  with  the  above  technique  and  with  a  certain 
tube  length  of  the  microscope,  viewed  with  a  1/12  oil  immersion 


Counting   Bacteria.  925 


objective,   indicates   the   following   number   of   bacteria   for  the 
various  fields  which  are  designated  by  letters : 

In  1/4  of  square  a  =  40,000,000  per  c.  c.  of  milk 
In  1/2  of  square  a  =  20,000,000  per  c.  c.  of  milk 
In  total  square  a  =  10,000,000  per  c.  c.  of  milk 
In  1/4  of  square  b  =  8,000,000  per  c.  c.  of  milk 
In  y2  of  square  b  =  4,000,000  per  c.  c.  of  milk 
In  total  square  b  =  2,000,000  per  c.  c.  of  milk 

In  circle   c  =    1,000,000  per  c.  c.  of  milk 

In  total  field  of 

observation     =      800,000  per  c.  c.  of  milk 

The  total  number  of  bacteria  found  in  all  the  counted  fields 
is  multiplied  by  the  relative  number  corresponding  to  the  field  of 
the  size  that  was  counted  and  divided  by  the  number  of  counted 
fields.  If,  for  instance,  in  20  ocular  fields  of  size  "a"  Skar  found 
the  number  to  be  150  bacteria,  then  these  figures  give : 

15QX20>000'Q°Q  =150X500>000=75>000>000  per  c.  c.  of  milk. 

Skar  always  found  many  more  bacteria  by  this  method  than 
were  found  by  the  plate  method  (2  to  70  times  as  many). 

The  direct  counting  is  more  rapid  and  more  accurate  than 
the  plate  counting  method. 

As  already  mentioned,  for  practical  control  work  the  counting 
of  bacteria  may  be  omitted.  In  this  work  the  reductase  test  offers 
a  quicker  determination  of  the  spoiled  condition  of  the  milk. 

For  special  examinations  the  following  methods  are  recom- 
mended: For  determining  age  and  decomposition  the  reductase 
test  and  periodically  repeated  acid  tests,  besides  the  microscopical 
examination  of  the  sediment,  should  be  applied. 

For  determining  decomposition  of  pasteurized  milk,  the  per- 
oxydase  test,  in  combination  with  the  reductase  test,  and,  at  times 
also  the  catalase  test  and  microscopic  examination  of  the  sediment, 
should  be  used. 

For  the  judgment  of  dirty  milk,  the  determination  and  esti- 
mation of  the  dirt  content,  the  reductase  test,  periodical  acid  test 
and  microscopic  examination  of  the  sediment  should  be  made. 

Inflammation  of  the  Udder. 

(a)  Market  milk: 

1.  Determination  of  the  quantity  and  appearance  of 

the  centrifugal  slime. 

2.  Microscopic    examination    of    the    sediment    for 

parenchyma  cells  and  the  presence  of  animal 
forms  of  streptococci. 
3.     In  tuberculosis :     Inoculate. 

(b)  Individual  samples: 

1.     Trommsdorff  test. 

15 


226  Milk   Inspection. 


2.  Microscopical  test  of  the  sediment  and  examina- 

tion as  to  the  presence  of  parenchyma  cells  and 
diplococci,  streptococci  of  the  short  and  long 
forms,  particularly  the  animal  types  or  the 
pyogenes  or  tuberculosis  bacillus. 

3.  If  necessary  the  catalase  test  or  examination  for 

amylase. 

(c)     Samples  from  individual  quarters: 

1.  Trommsdorff  or  sediment  tests. 

2.  Microscopy  and,  if  necessary,  inoculation. 

3.  Catalase  or  amylase  test. 

In  examinations  for  milk  defects,  the  following  tests  are 
recommended : 

1.  Tests  with  the  senses. 

2.  Shaking  test  (soapy  milk). 

3.  Eeductase  test    (frequently  the  reduction  appears  very 

slowly,  for  instance,  with  tallowy  and  soapy  milk). 

4.  Acid  tests. 

5.  Historical   consideration    of    the    conditions    of    stables, 

pasturage,  litter,  feed  and  water,  preparation  of  milk. 

6.  Fermentation  test. 

7.  Cultivation  of  bacteria  from  the  milk,  feed,  pastures,  etc., 

at  temperatures  at    which    the    defects    in    the    milk 
appeared. 

8.  Examination  of  cultures  in  sterilized  milk. 

(a)  Pure  cultures, 

(b)  Special  mixtures  of  colonies. 

The  veterinarian  should  also  be  able  to  conduct  the  routine 
examination  methods  usually  conducted  in  the  milk  laboratory 
and  the  preliminary  chemical  tests  for  adulteration,  provided  food 
chemists  are  not  available  in  such  localities.  It  would  lead  too 
far  to  mention  at  this  time  all  the  methods  which  may  be  applied 
in  suspected  adulterations.  Only  a  few  methods  will  be  described, 
particularly  those  which  are  employed  at  the  official  milk  labora- 
tory in  Munich. 

Determination  of  the  specific  gravity  of  milk.  It  is  best  to 
test  the  milk  for  its  specific  gravity  after  heating  it  to  15°  C.  or 
in  the  neighborhood  of  this  temperature.  The  milk  is  shaken 
up  and  it  is  advisable  to  make  the  test  in  suspended  cylinders  with 
the  aid  of  an  aerometer  and  a  thermometer.  It  is  not  advisable 
to  use  aerometers  into  which  thermometers  are  fused.  The  lac- 
todensimeter  used  for  milk  must  be  officially  tested.  The  specific 
gravity  of  milk  varies  in  accordance  with  its  contents  in  dis- 
solved, suspended  and  emulsified  ingredients. 

The  lactodensimeter  is  slowly  immersed  in  the  milk  and 
should  not  touch  the  walls  of  the  cylinder.  After  the  instrument 
has  come  to  a  rest,  the  place  at  which  the  level  of  the  fluid  touches 


Specific  Gravity.  927 


the  lactodensimeter  is  read.  The  numbers  on  the  lactodensimeter 
indicate  the  second,  third  and  fourth  decimals  of  the  specific 
gravity.  For  each  additional  degree  above  15°  C.,  0.2  should  be 
added  to  the  reading  of  the  lactodensimeter,  and  for  each  degree 
below  15°  C.,  0.2  should  be  deducted.  In  this  way  the  corrected 
readings  of  the  lactodensimeter  are  obtained,  before  which  must 
be  placed  1.0  in  order  to  obtain  the  specific  gravity.  The  Munich 
lactodensimeter  which  is  adjusted  to  a  temperature  of  15°  C.  is 
recommended  for  general  use. 

The  specific  gravity  of  the  milk  may  also  be  determined  by 
the  so-called  pyknometer.  This  method  is  suitable  for  small 
quantities  of  milk.  A  third  method  of  determination  of  the  specific 
gravity  is  Westphal's  modification  of  Mohr's  balance.  This  is  so 
constructed  that  the  lever  arm  of  the  balance  from  its  zero  point 
(the  axis  of  the  balance)  is  provided  with  9  notches  at  such  dis- 
tances, that  a  rider  suspended  on  it  indicates  from  1  to  10  times 
its  weight,  depending  upon  whether  it  is  pushed  towards  the 
end  of  the  arm  or  towards  its  axis.  Point  10  at  the  end  of  the 
arm  is  provided  with  a  loop.  A  weight  A,  suspended  in  the  loop 
of  point  1,  acts  on  point  1  only  as  a  weight  of  A/10  at  point  10. 

The  weights  A,  Ai,  and  A2,  may  be  mutually  interchanged  and 
indicate  the  integer  and  the  first  decimal  figure  of  the  specific 
gravity,  depending  upon  whether  they  are  suspended  in  the  loop 
or  in  the  notches.  The  weight  B=l/10  of  A,  and  indicates  when 
in  the  notches  1/100,  while  C  represents  1/10  of  B  and  when  in 
the  notches  indicates  the  1/1000  of  the  specific  gravity. 

By  shifting  the  weight  C  between  two  notches  the  fourth 
decimal  point  may  also  be  approximately  established. 

Hydrometers  made  of  glass  and  the  use  of  separate  ther- 
mometers are  recommended. 

The  specific  gravity  of  market  milk  varies  between  1,029  to 
about  1,033. 

The  increased  or  decreased  specific  gravity,  as  compared  with 
the  average  specific  gravity  of  the  milk  of  the  respective  locality, 
can  at  the  most  only  be  suspected  as  being  caused  by  dilution  with 
water  or  by  removal  of  the  cream.  In  case  of  double  adulteration 
the  specific  gravity  may  remain  normal. 

After  the  specific  gravity  has  been  determined,  the  fat  content 
is  established  by  one  of  the  ordinary  empiric  methods.  Gerber's 
acidbutyrometric  method  is  employed  at  the  milk  control  station 
of  Munich. 

The  following  apparatus  is  needed  for  this  method. 

1.  Centrifuge. 

2.  Butyrometer     (round     butyrometer,     flat     butyrometer, 
"optical"  butyrometer)  which  is  a  milk  receptacle,  ending  in  a 
graduated  tube  into  which  are  poured  sulphuric  acid,  amyl  alcohol 
and  milk,  and  which  is  closed  by  means  of  a  rubber  stopper. 

3.  A  10  c.  c.  pipette  or  an  automatic  measure  adjusted 


228  Milk   Inspection. 


10  c.  c.,  for  measuring  the  sulphuric  acid,  an  11  c.  c.  pipette  for 
milk  and  a  1  c.  c.  pipette  or  a  corresponding  automatic  measure 
for  amyl  alcohol. 

4.  Commercial  sulphuric  acid  of  a  specific  gravity  of  1,820 
to  1,825  (at  15°  C.). 

5.  Amyl  alcohol  with  a  specific  gravity  of  about  0.815  (at 
15°  C.)  and  a  boiling  point  of  128  to  130°  C. 

6.  Shaking  apparatus  with  a  protective  cover. 

7.  Water  bath. 

First  sulphuric  acid  (10  c.  c.)  is  poured  into  the  butyrometer, 
then  11  c.  c.  of  milk,  and  finally  1  c.  c.  of  amyl  alcohol.  The  tube 
is  closed  with  a  rubber  stopper  and  then  roughly  shaken.  Through 
mixing,  the  contents  become  greatly  heated.  After  the  disappear- 
ance of  all  flakes  and  after  the  tube  has  been  held  for  several 
minutes  at  65°  C.,  it  is  centrifugalized.  Following  the  centrifu- 
galization  it  is  again  heated  at  65°  C.  and  then  quickly  read. 

In  order  to  avoid  the  more  or  less  dangerous  handling  of 
sulphuric  acid,  Sichler's  "sinacid"  and  Gerber's  "sal"  methods 
have  recently  been  inaugurated,  in  which  alkaline  salt  solutions 
are  employed  instead  of  the  sulphuric  acid.  The  results  are  ap- 
proximately the  same  as  in  the  acid  butyrometers. 

[In  the  United  States  the  most  popular  method  for  determin- 
ing the  amount  of  fat  in  milk  is  by  the  Babcock  test.  If  carefully 
applied  the  results  can  be  relied  upon  without  question. 

In  the  application  of  this  test  sulphuric  acid  is  used  to  free 
the  fat  globules  by  dissolving  the  casein.  Then  by  proper  cen- 
trifuging  the  fat  is  collected  in  such  a  manner  that  it  may  be 
readily  measured. 

For  the  execution  of  the  test  special  test  bottles  are  provided. 
A  definite  amount  of  milk  (17.6  c.  c.)  is  placed  into  a  test-bottle 
to  which  17.5  c.  c.  of  commercial  sulphuric  acid  of  a  specific  gravity 
of  1.82  to  1.85  is  added  by  means  of  a  pipette,  burette  or  other 
measuring  apparatus.  The  contents  are  then  thoroughly  and 
carefully  mixed,  as  a  result  of  which  the  fluid  turns  brown  and 
becomes  somewhat  heated.  The  bottles  are  then  placed  into  a 
centrifuge  which  is  specially  constructed  for  this  purpose,  and 
centrifuged  for  5  minutes  at  900  to  1,200  revolutions  per  minute. 
After  removing  the  bottles  from  the  centrifuge  they  are  filled  with 
hot  water  up  to  the  lower  part  of  the  neck  and  they  are  again 
centrifuged  for  two  minutes.  A  sufficient  amount  of  hot  water 
is  now  added  to  float  the  melted  fat  into  the  neck  of  the  bottle 
which  is  provided  with  a  graduated  scale,  and  the  centrifuging 
is  repeated  for  one  minute.  The  volume  of  fat  can  be  easily  read 
from  the  graduated  portion  of  the  bottle,  and  this  reading  should 
be  done  while  the  neck  of  the  bottle  is  still  hot. — Trans.] 

The  fat  content  of  the  milk  fluctuates  between  wide  limits. 
The  total  solids  and  the  fat-free  solids  may  be  established  with 


Calculation    of    Milk    Solids.  229 

the   aid   of   the   specific   gravity   and   the   obtained   fat   content. 

d=percentage  of  solids=i/>  X  f  +  2.665  X  -  In  this 

s 

equation  f=fat  content  and  s=specific  gravity. 

Fleisclimann  has  prepared  two  tables  for  the  values  of  y^Xf 

and  for  the  value  of  2,665  X  —  '  for  the  specific  gravity 

S 

from  1,028  to  1,0369  and  for  2.5%  to  5.49%  of  fat,  so  that  through 
simple  addition  of  the  determined  values,  the  respective  content 
of  solids  can  be  established. 

Still  simpler  is  the  calculation  of  the  solids  by  Ackermann's 
"slide-ruler,"  which  consists  of  two  disks  united  at  the  turning 
point  and  which  slide  against  each  other.  The  larger  of  these 
contains  the  numbers  for  the  solids  and  fat  contents,  while  the 
smaller  has  the  numbers  for  the  specific  gravity.  By  turning  the 
small  disk  the  established  specific  gravity  number  and  the  fat  con- 
tent number  of  the  tested  sample  are  placed  opposite  each  other. 
An  indicator  fastened  to  the  inside  disk  points  to  the  amount  of 
the  total  solids. 

The  amount  of  fat-free  solids  is  obtained  by  subtracting  the 
percentage  of  fat  from  the  percentage  of  total  solids.  This  is  an 
important  factor  in  suspected  cases  of  adulteration.  Marked  dif- 
ferences are  the  result  of  artificial  influences  but  in  individual 
samples  the  difference  may  be  due  to  natural  fluctuations. 

Milk  with  a  high  fat  content  has  as  a  rule  more  fat-free  solids. 
The  milk  of  cows  of  the  highlands  has  more  fat-free  solids  than 
the  milk  of  cows  from  the  lowlands. 

According  to  Fleisclimann,  it  should  be  noted  that  the  fluctua- 
tions of  the  different  values  indicated  herein,  vary  in  the  different 
milking  periods  as  compared  with  the  annual  average.  These 
fluctuations  may  amount  to: 

10%  in  the  lactodensimeter  reading  (specific  gravity). 

30%  in  the  fat  content. 

14%  in  the  total  solids. 

10%  in  the  fat-free  solids. 

According  to  Fleisclimann,  the  fat-free  solids  do  not  fall  below 
7.9%,  and  the  specific  gravity  of  the  total  solid  matter  (m)  which 
may  be  determined  by  the  following  formula : 

s  X  d 

s  X  d— 100s  +  100 

exceeds  only  exceptionally  1.4  and  is  usually  1.31  to  1.36. 

Excepting  the  milk  of  individual  cows  or  that  of  a  few  cows, 
according  to  the  agreement  of  German  food  chemists,  the  presence 
of  adulteration  is  established  as  follows: 

1.     Adulteration  with  water  when  the  specific  gravity  of  the 


230  Milk   Inspection. 


milk  is  below  1 . 028,  that  of  the  serum  below  1 . 026  and  the  content 
of  fat-free  solids  falls  considerably  below  8%. 

2.  Cream  has  been  removed  from  the  milk  when  in  the  pres- 
ence of  an  increased  specific  gravity  of  the  milk  and  normal  specific 
gravity  of  the  serum  or  normal  content  of  fat-free  solids,  the  per- 
centage of  fat  content  of  the  milk  solids  falls  considerably  below 
20%  ;  that  is,  the  specific  gravity  of  the  latter  is  increased  consider- 
ably above  1.4. 

3.  Adulteration  with  water  together  with  removal  of  some 
of  the  cream  may  be  suspected  when  with  a  normal  specific  gravity 
of  the  milk,  that  of  the  serum  falls  below  1.026,  and  with  a  dimin- 
ished amount  of  all  the  ingredients  of  the  milk  the  fat  content  of 
the  solids  falls  considerably  below  20%  ;  that  is,  the  specific  gravity 
of  the  latter  is  increased  considerably  over  1.4.    The  percentage 
of  fat  contents  of  the  solids  is  obtained  from  the  following  formula : 

f  X  100. 


At  the  same  time  it  must  be  remembered  that  no  definite 
figures  of  limitation  should  exist  and  that  only  comparative  figures 
are  convincing.  The  sample  for  comparative  tests  may  be  ob- 
tained by  informing  the  manager  of  the  dairy  or  the  responsible 
producer  that  the  milk  is  suspected  of  being  watered,  and  he  is 
directed  to  devote  special  attention  to  the  milk  production  and  its 
subsequent  handling.  If  following  this  procedure  the  milk  becomes 
notably  changed  the  test  may  be  considered  as  comparative,  pro- 
vided that  it  is  not  preferred  to  undertake  immediately  an  official 
comparative  test.  This  must  be  done  as  quickly  as  possible,  and 
not  later  than  the  third  day  after  the  suspicion  has  been  estab- 
lished. According  to  Herz  the  following  formulas  apply  in  the 
calculation  of  adulterations : 

w  =  the  added  water  contained  in  100  parts  of  milk. 

v  ==  the  added  water  to  100  parts  of  milk. 

p  =  the  fat  removed  from  100  parts  of  milk. 

F!  =  the  fat-free  solids  of  the  stable  sample. 

r2  =  the  fat-free  solids  of  the  suspected  market  sample. 

fi  =  fat  contents  of  the  stable  sample. 

f2  =  fat  contents  of  the  suspected  market  sample. 

M  =  100  —  w,  the  amount  of  original  undiluted  milk  contained 
in  100  parts  of  watered  milk. 

100  X   (r,—  r,) 


w 


100  X   (r,  — r2) 


f.X  (f,- 

P 


. 


Detection    of    Adulteration.  231 

Finally  in  combined  adulteration  we  have  : 

f          MX  ft—  100  f,1        ff,—  M  X  £—100  f,-| 

L10U          M        -J"  ~w 


100 

Other  formulas  according  to  Vogel  are : 
The  addition  of  water  in  per  cent 

=  Y  x  10°  — 10° 

The  removed  amount  of  fat  in  per  cent 

=  100  X  -^F^2 
ii 

or  according  to  Bohmlander : 
v  =  —     X  w  —  W,  in  which  w  =  the  contents  of  water  in  the 

1*2 

suspected  sample  and  W  =  the  contents  of  water  of  the 
unsuspected  sample,  and 

E  =  100  1 1— 


fi  — r2 

(E  =  removed  fat  in  %  of  the  fat  content) 

The  establishment  of  the  suspicion  and  the  establishment  of 
the  amount  of  adulteration  are  greatly  supported  by  the  examina- 
tion of  the  milk  serum  free  from  proteins,  which  contains  the  sub- 
stances dissolved  in  the  milk,  the  content  of  which  is  subject  to 
only  the  slightest  variations.  The  examination  is  carried  out 

1.  Through  the  specific  gravity,  or 

2.  Through  refractometric  observations. 

It  is  best  to  prepare  the  serum  according  to  Ackermann  by  the 
addition  of  0 . 25  c.  c.  of  a  solution  of  calcium  chloride  of  a  specific 
gravity  of  1.1375,  to  30  c.  c.  of  milk,  which  mixture  is  thoroughly 
shaken  in  a  reagent  tube.  The  tube  is  closed  with  a  rubber  stopper 
through  which  a  glass  tube  is  inserted  as  a  reflux  condenser, 
and  it  is  then  heated  to  boiling  for  15  minutes.  The  tubes  are 
then  rinsed  in  cold  water  and  the  condensation  water  of  the  cool- 
ing tube  is  united  with  the  serum  by  slow,  repeated  and  careful 
shaking.  With  milk  which  is  in  a  state  of  decomposition,  the  milk 
serum  turns  cloudy  and  the  values  of  refraction  are  also  changed. 
Milk  from  affected  udders  which  is  considerably  changed,  fre- 
quently curdles  only  following  the  addition  of  double  quantities 
of  calcium  chloride  solution.  Differences  in  the  refraction  values 
of  2.4  to  2.50  indicate  about  a  10%  adulteration.  The  removal 
of  cream  does  not  change  the  refraction  value  of  the  milk. 

For  refraction  the  serum  prepared  according  to  Ackermann 
does  not  have  to  be  filtered,  but  this  should  be  done  for  the  deter- 


232  Milk   Inspection. 


ruination  of  the  specific  gravity,  which  is  usually  1.026  to  1.027. 
In  applying  this  method  it  may  become  necessary  to  use  larger 
amounts  of  serum.  Differences  of  about  0.0025  in  the  specific 
gravity  indicate  mixing  with  about  10%  of  water. 

The  positive  demonstration  of  nitrates  in  milk  is  always  a 
proof  that  the  milk  has  been  watered  and  with  water  that  should 
be  considered  as  objectionable  as  drinking  water,  or  that  has  been 
used  for  the  rinsing  of  the  milk  containers,  and  which  according 
to  its  quality  must  be  considered  as  impure.  Milk  which  gives  the 
nitrate  reaction  should  therefore  be  considered  not  only  as  adul- 
terated but  also  as  being  spoiled  in  the  sense  of  the  pure  food 
law  and  even  as  injurious  to  health.  The  nitrate  test  may  become 
of  great  importance  for  the  conviction  of  certain  persons,  when 
for  instance  the  water  of  the  well  at  the  barn  contains  nitrates, 
while  the  one  at  the  farmhouse  has  no  nitrates  and  vice  versa. 
According  to  Rothenfusser  the  nitrate  test  is  a  substantiating 
proof  of  great  importance.  Milk  samples  contaminated  with 
manure  and  litter  do  not  give  the  nitrate  test. 

Nitrates  and  nitrites  do  not  occur  in  milk  of  animals  fed  and 
cared  for  in  the  usual  manner  on  the  farm.  Rothenfusser  ascer- 
tained that  the  unavoidable  residue  of  water  used  in  rinsing  the 
milk  containers  represents  only  a  tenth  or  a  twentieth  part  of  the 
amount  of  water,  which  is  necessary  to  make  a  1%  addition  and 
that  the  residue  of  water  retained  in  the  rinsed  vessel  must  possess 
the  qualities  of  ditch  water  in  order  to  be  capable  of  adding  to 
the  milk  a  demonstrable  amount  of  nitrates.  According  to  Rothen- 
fusser the  test  may  be  carried  out  to  the  best  advantage,  by  placing 
into  small,  flat,  white  porcelain  vessels  2  c.  c.  of  pure  sulphuric 
acid  of  a  specific  gravity  of  1.84,  over  which  a  small  amount  of 
crystallized  diphenylamin  is  sprinkled  from  a  sprinkling  cylinder 
(a  reagent  tube  with  a  perforated  cork  stopper,  into  which  a  short 
glass  tube  of  about  3  mm.  inside  diameter  is  inserted). 

Then  a  small  quantity  of  chloride  of  calcium  serum  of  the 
milk  to  be  examined  is  allowed  to  flow  in  from  the  edges  of  the 
vessel.  The  appearance  of  the  grayish-blue  clouds  and  stripes  in 
the  fluid  indicates  the  presence  of  nitric  acid  in  the  milk. 


CHAPTEK  XI. 

FUNDAMENTAL   PRINCIPLES   OF   LEGISLATIVE 
MILK    CONTROL. 

The  practical  inauguration  of  milk  hygiene  is,  of  course,  only 
possible  where  proper  laws  and  ordinances  are  at  our  command 
for  the  accomplishment  of  the  result.  The  laws,  regulations  and 
ordinances  of  the  various  states  and  municipalities  promulgated 
for  the  purpose  of  controlling  the  milk  supply  lack  uniformity  in 
many  of  their  essential  requirements,  and  it  is  apparent  that  these 
measures  were  drafted  to  meet  the  conditions  prevailing  in  the 
different  localities.  Furthermore,  a  general  federal  control  of  the 
milk  supply  cannot  be  considered  practicable,  except  possibly  in 
so  far  as  interstate  shipments  of  milk  may  be  involved. 

The  individual  states  may  foster  the  interests  of  public  health 
by  the  inauguration  of  such  legislative  measures  as  will  assure  a 
wholesome  and  clean  milk  supply  for  the  different  municipalities 
within  the  state,  particularly  when  the  necessity  prevails  for  the 
shipment  of  milk  from  long  distances  to  a  city.  For  this  purpose 
the  state  might  well  be  divided  into  districts,  supervised  by  com- 
petent inspectors  who  would  primarily  inspect  the  cattle  and 
stables,  the  methods  of  producing  the  milk  and  its  transportation. 
Such  inspectors  could  also  be  of  splendid  service  in  the  control 
and  possible  eradication  of  contagious  diseases  which  not  only 
may  have  an  effect  on  milk  production,  but  which  are  also  of  im- 
portance to  animal  industry  in  general. 

The  largest  proportion  of  actual  control  work,  however,  will 
have  to  be  carried  out  by  the  different  municipalities,  where,  with 
proper  ordinances  and  with  competent  inspectors  and  laboratory 
officials,  an  efficient  control  could  be  maintained  which  would  assure 
a  wholesome  milk  supply  to  the  consumers.  It  is  apparent  that 
such  ordinances  must  be  drafted  to  meet  the  local  conditions,  which 
would  depend  upon  the  dairying  industry  in  that  section,  the  num- 
ber of  the  population  and  the  feelings  of  the  people. 

While  there  exists  no  uniformity  in  the  regulations  govern- 
ing milk  inspection  and  milk  hygiene  in  general  in  the  different 
parts  of  the  United  States,  the  necessity  for  at  least  a  uniform 
standard  has  been  met  in  a  most  satisfactory  manner.  After  con- 
siderable agitation  medical  milk  commissions  were  organized  in 

233 


234  Principles   of   Legislative   Milk    Control. 

various  cities  of  the  United  States  for  the  purpose  of  establishing 
milk  standards  and  also  of  obtaining  such  legislation  as  would 
assure  clean  and  wholesome  milk  to  the  communities.  The  organi- 
zation of  milk  commissions  in  this  country  was  undoubtedly  an 
important  step  towards  the  improvement  of  the  quality  of  milk, 
and  only  by  the  concerted  work  of  these  and  similar  organizations 
can  the  country  at  large  be  assured  of  a  proper  milk  supply.  It 
is  regrettable  that  milk,  the  most  important  food,  is  not  considered 
by  the  laity  of  sufficient  importance  to  be  subjected  to  the  most 
rigid  control,  especially  since  it  constitutes  the  principal,  and  in 
early  life  the  only  food  of  children. 

The  second  report  of  the  Commission  on  Milk  Standards,  ap- 
pointed by  the  New  York  Milk  Committee,  embodies  the  principles 
for  a  wholesome  milk  supply  and  would  serve  well  as  a  basis  for 
the  formulation  of  effective  ordinances.  Therefore  it  is  deemed 
advisable  to  reproduce  these  principles  from  the  Public  Health 
Eeports  of  August  22,  1913,  United  States  Public  Health  Service. 

Need  of  Milk  Control. 

Proper  milk  standards,  while  they  are  essential  to  efficient 
milk  control  by  public  health  authorities  and  have  as  their  object 
the  protection  of  the  milk  consumer,  are  also  necessary  for  the 
ultimate  well-being  of  the  milk  industry  itself.  Public  confidence 
is  an  asset  of  the  highest  value  in  the  milk  business.  The  milk 
producer  is  interested  in  proper  standards  for  milk,  since  these 
contribute  to  the  control  of  bovine  tuberculosis  and  other  cattle 
diseases  and  distinguish  between  the  good  producer  and  the  bad 
producer.  The  milk  dealer  is  immediately  classified  by  milk 
standards,  either  into  a  seller  of  first-class  milk  or  a  seller  of 
second-class  milk,  and  such  distinction  gives  to  the  seller  of  first- 
class  milk  the  commercial  rewards  which  he  deserves,  while  it 
inflicts  just  penalties  on  the  seller  of  second-class  milk.  For  milk 
consumers,  the  setting  of  definite  standards  accompanied  by  proper 
labeling  makes  it  possible  to  know  the  character  of  the  milk  which 
is  purchased  and  to  distinguish  good  milk  from  bad  milk.  In  the 
matter  of  public  health  administration,  standards  are  absolutely 
necessary  to  furnish  definitions  around  which  the  rules  and  regula- 
tions of  city  health  departments  can  be  drawn,  and  the  milk  supply 
efficiently  controlled. 

Public  Health  Authorities. 

While  public  health  authorities  must  necessarily  see  that  the 
source  of  supply  and  the  chemical  composition  should  correspond 
with  established  definitions  of  milk  as  a  food,  their  most  important 
duty  is  to  prevent  the  transmission  of  disease  through  milk.  This 
means  the  control  of  infantile  diarrhea,  typhoid  fever,  tuberculosis, 


Disease    Transmitted    Through    Milk.  235 

diphtheria,  scarlet  fever,  septic  throat  infections,  and  other  infec- 
tious diseases  in  so  far  as  they  are  carried  by  milk. 

Septic  Sore  Throat. 

Septic  sore  throat  deserves  special  mention  because  of  the 
frequency  in  recent  years  with  which  outbreaks  of  this  disease 
have  been  traced  to  milk  supplies.  The  suggestion  has  been  made 
that  the  infection  of  the  milk  is  due  to  udder  infection  of  the  cow 
and  on  the  other  hand  it  has  been  suggested  that  it  is  due  to  con- 
tact with  infected  persons.  The  uncertainty  can  not  be  dispelled 
until  cases  of  septic  sore  throat  are  regularly  reported  and  tabu- 
lated by  public  health  authorities.  The  commission  therefore  rec- 
ommends that  public  health  authorities  make  septic  sore  throat 
a  reportable  disease. 

Economic  Problem. 

The  commission  recognizes  the  magnitude  of  the  milk  industry, 
and  that  the  improvement  of  milk  supplies  is  primarily  an  eco- 
nomic problem.  The  success  achieved  by  the  experiment  in  milk 
production,  which  has  been  carried  out  on  a  very  large  scale  by 
the  New  York  Dairy  Demonstration  Co.,  is  an  illustration  of  the 
fact  that  an  extra  price  or  premium  paid  to  the  producer  for 
cleanliness  and  care  will  bring  results  far  more  quickly  and 
certainly  than  instructions  or  official  inspection.  But  while  the 
basic  problem  is  economic,  and  must  eventually  be  solved  by  com- 
merce, public  health  authorities  must  show  the  way  and  must  estab- 
lish standards  and  regulations  in  the  interest  of  consumers,  the 
value  of  which  even  the  consumers  themselves  often  fail  to  ap- 
preciate. 

Legal  Requirements. 

A  prime  requisite  of  effectiveness  is  that  local  milk  laws  shall 
not  exceed  sanitary  limitations.  The  commission  has  not  entered 
into  a  discussion  of  fundamental  state  laws,  but  it  recommends 
that  state  laws  be  amended  wherever  necessary  in  order  that  every 
municipality  may  have  the  legal  right  to  adopt  whatever  ordinances 
it  sees  fit  for  the  improvement  of  the  milk  supply.  The  commission 
advocates  that  local  health  laws  be  carefully  drawn  with  regard 
to  their  legality  under  the  general  laws  of  the  localities  to  which 
they  apply,  since  a  decision  against  a  milk  law  in  one  locality  is 
liable  to  be  used  as  a  precedent  against  milk  laws  elsewhere. 

Standard  Rules  and  Regulations. 

The  commission  has  drawn  up  a  set  of  standard  rules  and 
regulations  for  the  control  of  milk.  These  are  the  result  of  a  study 
of  the  printed  rules  and  regulations  of  the  cities  of  the  United 
States  and  of  foreign  countries  and  represent  an  immense  amount 


236  Principles   of   Legislative   Milk    Control. 

of  work  on  the  part  of  the  special  committee  of  the  commission 
to  which  the  task  was  assigned.  Some  communities  are  in  a  posi- 
tion to  adopt  all  of  these  rules  and  regulations  at  the  present  time, 
while  other  communities  will  be  obliged  to  adopt  a  few  rules  at  a 
time  as  public  sentiment  and  local  conditions  warrant.  It  is  real- 
ized that  some  of  the  rules  may  have  to  be  modified  to  meet  local 
conditions.  It  seems  wise  to  the  commission  to  divide  the  regula- 
tions into  two  parts :  First,  requirements,  under  which  head  are 
set  down  those  provisions  which  are  so  fundamentally  necessary 
that  no  community  is  justified  in  compromising  on  them ;  second, 
recommendations,  under  which  head  are  set  down  provisions  which 
are  necessary  for  a  good  milk  supply,  but  on  which  there  can  be 
a  certain  amount  of  latitude  for  compromise  by  those  communi- 
ties in  which  public  sentiment  is  not  ready  to  support  more  than 
a  moderate  degree  of  protection  of  human  life. 

Administrative  Equipment. 

Another  prime  requisite  is  that  the  administrative  depart- 
ments shall  be  adequately  equipped  with  men,  money,  and  labora- 
tory facilities.  In  smaller  communities  cooperation  between  local 
boards  of  health  to  the  extent  of  exchanging  reports  would  elimi- 
nate much  duplication.  Where  a  community  can  not  maintain  a 
laboratory  it  can  enter  into  laboratory  arrangements  with  other 
communities,  and  several  can  combine  in  the  use  of  a  common 
laboratory.  Much  of  the  expense  of  tuberculin  testing  can  be 
borne  by  the  national  and  state  governments.  The  commission 
is  of  the  opinion  that  results  can  not  be  expected  from  laws  where 
there  is  not  sufficient  appropriation  and  where  there  is  no  ma- 
chinery for  their  enforcement.  On  this  subject  the  commission 
passed  a  resolution  as  follows: 

Whereas  the  appropriations  generally  made  for  the  purposes  of  carrying  on 
laboratory  analyses  of  milk  are  now  in  most  cases  entirely  inadequate:  Therefore  be  it 

Resolved,  That  this  commission  recommends  for  the  consideration  of  the  authorities 
concerned  an  appropriation  of  funds  commensurate  with  the  importance  of  laboratory 
methods,  which  are  of  paramount  importance  in  the  hygienic  control  of  the  milk  supply. 

Grading  of  Milk. 

There  is  no  escape  from  the  conclusion  that  milk  must  be  graded 
and  sold  on  grade,  just  as  wheat,  corn,  cotton,  beef,  and  other 
products  are  graded.  The  milk  merchant  must  judge  of  the  food 
value  and  also  of  the  sanitary  character  of  the  commodity  in  which 
he  deals.  The  high-grade  product  must  get  a  better  price  than  at 
present.  The  low-grade  product  must  bring  less.  In  separating 
milk  into  grades  and  classes  the  commission  has  endeavored  to 
make  its  classification  as  simple  as  possible  and  at  the  same  time 
to  distinguish  between  milks  which  are  essentially  different  in 
sanitary  character. 


Pasteurization    of    Milk.  237 


In  general  two  great  classes  of  milk  are  recognized,  namely, 
raw  milk  and  pasteurized  milk.  Under  these  general  classes  there 
are  different  grades,  as  indicated  in  the  report  of  the  committee 
on  classification. 

Pasteurization. 

While  the  process  of  pasteurization  is  a  matter  which  has  at- 
tracted a  great  deal  of  attention  in  recent  years,  the  commission 
has  not  entered  into  any  discussion  of  its  merits  or  demerits,  but 
has  given  it  recognition  in  its  classification  as  a  process  necessary 
for  the  treatment  of  milk  which  is  not  otherwise  protected  against 
infection. 

The  commission  thinks  that  pasteurization  is  necessary  for  all 
milk  at  all  times,  excepting  grade  A,  raw  milk.  The  majority  of 
the  commissioners  voted  in  favor  of  the  pasteurization  of  all  milk, 
including  grade  A,  raw  milk.  Since  this  was  not  unanimous  the 
commission  recommends  that  the  pasteurization  of  grade  A,  raw 
milk,  be  optional. 

The  process  of  pasteurization  should  be  under  official  super- 
vision. The  supervision  should  consist  of  a  personal  inspection 
by  the  milk  inspector.  The  inspections  shall  be  as  frequent  as 
possible.  Automatic  temperature  regulators  and  recording  ther- 
mometers should  be  required  and  the  efficiency  of  the  process 
frequently  determined  by  laboratory  testing. 

Pasteurizing  Temperatures. 

The  destruction  of  the  chemical  constituents  of  milk  by  heat 
occurs  at  higher  temperatures  than  those  necessary  for  the  destruc- 
tion of  the  bacteria  of  infectious  diseases  transmissible  by  milk. 

The  commission  passed  a  resolution  regarding  the  temperature 
of  pasteurization  as  follows: 

That  pasteurization  of  milk  should  be  between  the  limits  of  140°  F.  and  155°  F.  At 
140°  F.  the  minimum  exposure  should  be  20  minutes.  For  every  degree  above  140°  F.  the 
time  may  be  reduced  by  1  minute.  In  no  case  should  the  exposure  be  for  less  than  5 
minutes. 

In  order  to  allow  a  margin  of  safety  under  commercial  condi- 
tions the  commission  recommends  that  the  minimum  temperature 
during  the  period  of  holding  should  be  made  145°  F.  and  the  hold- 
ing time  30  minutes.  Pasteurization  in  bulk  when  properly  carried 
out  has  proven  satisfactory,  but  pasteurization  in  the  final  con- 
tainer is  preferable. 

It  is  the  sense  of  the  commission  that  pasteurization  in  the 
final  container  should  be  encouraged. 


238  Principles    of   Legislative   Milk    Control. 


Labeling  and  Dating  of  Milk. 

The  commission  voted  that  all  milk  should  be  labeled  and 
marked  with  the  grade  in  which- it  is  to  be  sold.  In  dating  milk 
uniform  methods  should  be  adopted  for  all  grades  of  both  raw 
milk  and  pasteurized  milk,  both  using  the  day  of  the  week  or  both 
using  the  day  of  the  month.  All  milk  should  be  dated  uniformly 
with  the  date  of  delivery  to  the  consumer.  Eaw  milk  should  not 
be  dated  with  the  date  of  production,  while  pasteurized  milk  is 
dated  with  the  date  of  pasteurization,  since  this  places  certified 
milk  at  a  disadvantage  by  making  it  possible  for  pasteurized  milk 
of  a  lower  grade  to  carry  a  later  date.  The  stamping  on  the  label 
of  the  day  of  the  week  is  sufficient  for  dating. 

Bacteria. 

The  subject  of  bacteria  in  milk  received  more  attention  than 
any  other  matter  brought  before  the  commission.  The  commission 
recognizes  that  bacteria  in  milk  in  the  majority  of  instances  indicate 
dirt,  or  lack  of  refrigeration,  or  age,  while  in  the  minority  of 
instances  the  bacteria  of  disease  may  be  present.  The  routine 
laboratory  methods  for  examining  milk  have  as  their  purpose  only 
the  control  over  dirt,  refrigeration,  and  age,  and  it  is  a  rare  thing 
for  a  laboratory  to  undertake  the  examination  of  milk  for  the 
bacteria  of  disease  because  of  the  extreme  difficulties  in  detecting 
them.  The  more  efficacious  method  of  protecting  milk  from  infec- 
tion by  the  bacteria  of  human  contagion  is  by  medical,  veterinary, 
and  sanitary  inspection,  and  by  pasteurization.  Milk  with  a  high 
bacteria  count  is  not  necessarily  harmful,  but  when  used  as  a  food, 
particularly  for  children,  is  a  hazard  too  great  to  be  warranted. 
Milk  with  a  high  bacteria  count,  therefore,  should  be  condemned. 
Milks  with  small  numbers  of  bacteria  are  presumed  to  be  whole- 
some, unless  there  is  reasonable  ground  for  suspecting  that  they 
have  been  exposed  to  contagion. 

Bacterial  Standards. 

The  commission  recognizes  the  difficulty  in  interpreting 
bacteria  counts.  At  times  misleading  conclusions  have  been  drawn 
from  such  counts.  In  establishing  the  bacterial  standards  for  a 
city  it  is  always  necessary  to  take  into  consideration  the  necessary 
age  of  the  milk  and  in  lesser  measure  the  distance  hauled  and 
methods  employed  in  its  hauling.  It  will  always  be  possible  for 
a  community  which  consumes  milk  produced  on  its  own  premises, 
or  within  12  hours  of  its  production,  to  insist  upon  and  maintain 
a  lower  bacterial  standard  than  can  one  where  the  milk  is  hauled 


Bacterial   Standards.  239 


many  miles  into  town  in  a  wagon,  to  be  consumed  within  24  hours 
after  it  is  produced.  In  like  manner  this  second  type  of  city  can 
always  maintain  a  lower  bacterial  standard  than  a  city  where  the 
general  milk  supply  is  hauled  by  railroad  long  distances  and  is 
several  days  old  when  consumed.  In  drawing  conclusions  as  to 
the  relative  efficacy  of  milk  control  in  cities  comparisons  must  be 
made  between  cities  of  the  same  class. 

The  commission  deems  it  of  the  utmost  importance  that  some 
standard  method  should  be  adopted  for  estimating  and  comparing 
the  bacterial  character  of  milks,  since  by  this  means  only  is  it 
possible  to  grade  and  classify  milks  and  to  enforce  bacterial 
standards.  There  is  much  diversity  of  opinion  as  to  the  best 
method  of  valuing  bacteria  counts.  The  average  of  a  series  gives 
results  which  are  misleading  about  as  frequently  as  otherwise.  In 
the  average  a  single  high  figure  may  unduly  overbalance  a  large 
number  of  exceedingly  low  counts.  There  are  objections  to  the 
use  of  the  "median"  or  middle  number  when  the  counts  are  ar- 
ranged in  order  of  size,  for  the  reason  that  the  middle  figure  does 
not  distinguish  between  two  groups  in  one  of  which  there  may  be 
some  very  high  counts  above  the  median  and  in  the  other  of  which 
there  are  none.  The  method  of  dividing  results  into  groups  as 
recommended  by  the  American  Public  Health  Association,  while 
a  step  in  the  right  direction,  is  cumbersome  and  does  not  clearly 
indicate  whether  or  not  a  milk  conforms  to  a  given  bacterial 
standard. 

The  commission  passed  a  resolution  at  its  last  meeting  regard- 
ing the  number  of  bacterial  tests  necessary  to  determine  the  grade 
into  which  a  milk  falls,  as  follows: 

That  the  grade  into  which  a  milk  falls  shall  be  determined  bacteriologically  by  at 
least  five  consecutive  bacteria  counts  taken  over  a  period  of  not  less  than  one  week  nor 
more  than  one  month,  and  at  least  80  per  cent  (four  out  of  five)  must  fall  below  the  limit 
set  for  the  grade  for  which  the  classification  is  desired. 

Laboratory  Examinations  for  Bacteria. 

On  the  subject  of  laboratory  examinations  of  milk  for  bacteria 
the  commission  passed  the  following  resolutions: 

1.  That  the  interests  of  public  health  demand  that  the  control  of  milk  supplies, 
both  as  to  production  and  distribution,  shall  include  regular  laboratory  examinations  of 
milk  by  bacteriological  methods. 

2.  That  among  present  available  routine  laboratory  methods  for  determining  the 
sanitary  quality  of  milk  the  bacteria  count  occupies  first  place. 

3.  That  bacteriological  standards  should  be  a  factor  in  classifying  or  grading  milks 
of  different  degrees  of  excellence. 

4.  That  in  determining  the  grade  or  class  of  a  raw  milk  the  specimen  taken  for 
bacteriological  examination  should  be  of  milk  as  offered  for  sale. 

5.  That  there  should  be  bacteriological  standards  for  pasteurized  milk  which  should 
require  laboratory  examination  of  samples  immediately  before  pasteurization  as  well  as 
of  milk  offered  for  sale. 

6.  That  the  bacteria  count  of  milk  indicates  its  quality  and  history  as  it  is  modified 
by  contamination,  handling,   dirt,   temperature,   or  age.     A  high  count  indicates  the 
necessity  of  investigation  and  inspection. 


240  Principles   of   Legislative   Milk    Control. 

7.  That  there  be  adopted  as  standards  for  making  the  bacteria  count  the  standard 
methods  of  the  American  Public  Health  Association,  laboratory  section,  recommending, 
however,  the  following  amendments: 

A.  That  the  culture  medium  used  for  testing  milk  be  identical  in  its  composition 
and  reaction  with  the  culture  medium  used   for  the  testing  of  water  provided  in  the 
standard  methods  of  water  analyses  of  the  American  Public  Health  Association. 

B.  That  incubation  of  plate  cultures  be  made  at  37°  C.  for  48  hours. 

The  bacterial  standards  given  in  the  report  are  the  work  of  a 
special  committee  of  bacteriologists  who  considered  all  of  the  bac- 
terial standards  now  in  use.  It  is  believed  that  the  standards 
suggested  are  fair  and  wise  and  give  full  consideration  to  the 
state  of  the  industry  and  of  public  health  control.  The  commission 
believes  that  the  adoption  and  enforcement  of  these  bacterial 
standards  will  be  more  effective  than  any  other  one  thing  in  im- 
proving the  sanitary  character  of  public  milk  supplies.  The  en- 
forcement of  these  standards  can  be  carried  out  only  by  the 
regular  and  frequent  laboratory  examinations  of  milks  for  the 
numbers  of  bacteria  they  may  contain. 

Chemical  Standards. 

The  chemical  standards  suggested  are  the  work  of  a  special 
committee,  composed  of  chemists,  which  has  carefully  considered 
the  natural  composition  of  milk  and  the  Federal  and  State  stand- 
ards already  established.  The  standard  of  3.25  per  cent  fat  and 
8.5  per  cent  solids,  not  fat,  here  proposed  is  in  accordance  with 
the  recommendations  of  the  Association  of  Official  Agricultural 
Chemists  and  has  been  adopted  by  the  United  States  Department 
of  Agriculture  and  by  a  larger  number  of  States  than  has  any 
other  standard.  The  simplification  of  the  Babcock  test  makes  the 
determination  of  fats  and  solids  not  fat  an  easy  procedure  quickly 
applied.  Such  chemical  examinations  of  milk  can  be  readily 
adopted  and  executed  by  any  health-board  laboratory  at  a  very 
moderate  expense.  It  is  believed  that  such  chemical  standards  as 
are  suggested  will  inflict  no  real  hardship  on  the  milk  producers 
of  this  country  and  that  the  provision  regarding  substandard 
milks  is  a  liberal  one. 

Microscopic  Examination  of  Milk. 

Because  of  studies  which  have  been  made  during  the  past  year 
the  commission  thinks  it  wise  to  omit  temporarily  any  definite 
statement  on  the  subject  of  microscopical  examination  of  milk,  and 
the  determination  of  pus  and  bacteria  by  sedimentation  methods, 
until  further  studies  have  been  made.  A  special  subcommittee  has 
been  appointed  for  this  purpose  which  will  make  studies  during 
the  present  year  and  the  commission  will  take  action  on  this  matter 
at  one  of  its  later  meetings. 


Labeling  and   Grading  Milk.  241 

Mislabeling. 

The  commission  resolved  that  the  sale  of  milk  which  is  mis- 
labeled  or  misbranded  shall  be  punished  by  suitable  penalties. 

Publicity. 

The  commission  fully  considered  the  matter  of  the  publication 
of  laboratory  examinations  of  milk  by  city  and  town  health  authori- 
ties. When  proper  standards  and  regulations  are  established  and 
adequate  facilities  furnished  for  laboratory  work,  it  is  believed 
that  the  laboratory  tests  will  give  an  index  of  the  character  of 
the  milk  delivered  to  the  public  by  milk  sellers  which  is  entirely 
fair  and  impartial.  There  can  be  no  objection  to  publicity  under 
such  circumstances.  It  is  an  advantage  to  the  seller  of  high-grade 
milk.  It  is  an  advantage  to  the  consumer  who  desires  to  select  a 
high-grade  milk.  It  has  much  educational  value  both  to  producer 
and  consumer.  Therefore  the  commission  recommends  "that  the 
reports  of  laboratory  analyses  of  milk  made  by  departments  of 
health  be  regularly  published." 

Medical  Inspection. 

It  is  the  sense  of  the  commission  that  the  medical  inspection 
of  dairy  employees  should  be  emphasized  in  all  ways  possible. 

Milk  Dealer's  License. 

The  commission  resolved  that  a  dealer  shall  be  required  to 
have  a  permit  or  license  to  sell  any  grade  or  class  of  milk  and  to 
use  a  label  for  such  class  or  grade.  Such  permit  or  license  shall 
be  revoked  and  the  use  of  the  label  forbidden  when  the  local  health 
authorities  shall  determine  that  the  milk  is  not  in  the  class  or 
grade  designated. 

Designation  of  Grade. 

The  commission  resolved  that  the  grade  of  milk  shall  be  desig- 
nated by  letter.  It  is  the  sense  of  the  commission  that  the  essential 
part  is  the  lettering  and  that  all  other  words  on  the  label  are 
explanatory. 

In  addition  to  the  letters  of  the  alphabet,  used  on  caps  or 
labels,  the  use  of  other  terms  may  be  permitted  so  long  as  such 
terms  are  not  the  cause  of  deception. 

Caps  and  labels  shall  state  whether  milk  is  raw  or  pasteurized. 
The  letter  designating  the  grade  to  which  milk  belongs  shall  be 
conspicuously  displayed  on  the  caps  of  bottles  or  the  labels  on  cans. 

Classification  of  Milk. 

It  was  resolved  that  the  classification  of  milk  contained  in 
the  first  report  of  the  commission  be  amended  as  follows : 

Milk  shall  be  divided  into  three  grades,  which  shall  be  the 

16 


242  Principles   of   Legislative   Milk    Control. 

same  for  both  large  and  small  cities  and  towns,  and  which  shall 
be  designated  by  the  first  three  letters  of  the  alphabet.  The  re- 
quirements shall  be  as  follows: 

Grade  A. 

Raw  milk. — Milk  of  this  class  shall  come  from  cows  free  from  disease  as  determined 
by  tuberculin  tests  and  physical  examinations  by  a  qualified  veterinarian,  and  shall  be 
produced  and  handled  by  employees  free  from  disease  as  determined  by  medical  inspection 
of  a  qualified  physician,  under  sanitary  conditions  such  that  the  bacteria  count  shall  not 
exceed  100,000  per  cubic  centimeter  at  the  time  of  delivery  to  the  consumer.  It  is 
recommended  that  dairies  from  which  this  supply  is  obtained  shall  score  at  least  80  on 
the  United  States  Bureau  of  Animal  Industry  score  card. 

Pasteurized  milk. — Milk  of  this  class  shall  come  from  cows  free  from  disease  as 
determined  by  physical  examinations  by  a  qualified  veterinarian  and  shall  be  produced 
and  handled  under  sanitary  conditions  such  that  the  bacteria  count  at  no  time  exceeds 
200,000  per  cubic  centimeter.  All  milk  of  this  class  shall  be  pasteurized  under  official 
supervision,  and  the  bacteria  count  shall  not  exceed  10,000  per  cubic  centimeter  at  the 
time  of  delivery  to  the  consumer.  It  is  recommended  that  dairies  from  which  this  supply 
is  obtained  should  score  65  on  the  United  States  Bureau  of  Animal  Industry  score  card. 

The  above  represents  only  the  minimum  standards  under 
which  milk  may  be  classified  in  grade  A.  The  commission  recog- 
nizes, however,  that  there  are  grades  of  milk  which  are  produced 
under  unusually  good  conditions,  in  especially  sanitary  dairies, 
many  of  which  are  operated  under  the  supervision  of  medical 
associations.  Such  milks  clearly  stand  at  the  head  of  this  grade. 

Grade  B. 

Milk  of  this  class  shall  come  from  cows  free  from  disease  as  determined  by  physical 
examinations,  of  which  one  each  year  shall  be  by  a  qualified  veterinarian,  and  shall  be 
produced  and  handled  under  sanitary  conditions  such  that  the  bacteria  count  at  no  time 
exceeds  1,000,000  per  cubic  centimeter.  All  milk  of  this  class  shall  be  pasteurized  under 
official  supervision,  and  the  bacteria  count  shall  not  exceed  50,000  per  cubic  centimeter 
when  delivered  to  the  consumer. 

It  is  recommended  that  dairies  producing  grade  B  milk  should  be  scored  and  that 
the  health  departments  or  the  controlling  departments,  whatever  they  may  be,  strive  to 
bring  these  scores  up  as  rapidly  as  possible. 

Grade  C. 

Milk  of  this  class  shall  come  from  cows  free  from  disease  as  determined  by  physical 
examinations  and  shall  include  all  milk  that  is  produced  under  conditions  such  that  the 
bacteria  count  is  in  excess  of  1,000,000  per  cubic  centimeter. 

All  milk  of  this  class  shall  be  pasteurized,  or  heated  to  a  higher  temperature,  and 
shall  contain  less  than  50,000  bacteria  per  cubic  centimeter  when  delivered  to  the 
customer.  It  is  recommended  that  this  milk  be  used  for  cooking  or  manufacturing 
purposes  only. 

Whenever  any  large  city  or  community  finds  it  necessary,  on  account  of  the  length 
of  haul  or  other  peculiar  conditions,  to  allow  the  sale  of  grade  C  milk,  its  sale  shall 
be  surrounded  by  safeguards  such  as  to  insure  the  restriction  of  its  use  to  cooking 
and  manufacturing  purposes. 

Classification  of  Cream. 

Cream  should  be  classified  in  the  same  grades  as  milk,  in 
accordance  with  the  requirements  for  the  grades  of  milk,  excepting 
the  bacterial  standards  which  in  20  per  cent  cream  shall  not  exceed 
five  times  the  bacterial  standard  allowed  in  the  grade  of  milk. 


Chemical   Standards   for   Milk   Products.  243 

Cream  containing  other  percentages  of  fat  shall  be  allowed 
a  modification  of  this  required  bacterial  standard  in  proportion 
to  the  change  in  fat. 

Chemical  Standards. 

Cow's  milk. — Standard  milk  should  contain  not  less  than  8.5 
per  cent  of  milk  solids  not  fat  and  not  less  than  3.25  per  cent  of 
milk  fat. 

Skim  milk. — Standard  skim  milk  should  contain  not  less  than 
8.75  per  cent  of  milk  solids. 

Cream. — Standard  cream  contains  not  less  than  18  per  cent  of 
milk  fat  and  is  free  from  all  constituents  foreign  to  normal  milk. 
The  percentage  of  milk  fat  in  cream  over  or  under  that  standard 
should  be  stated  on  the  label. 

Buttermilk. — Buttermilk  is  the  product  that  remains  when  fat 
is  removed  from  milk  or  cream,  sweet  or  sour,  in  the  process  of 
churning.  Standard  buttermilk  contains  not  less  than  8.5  per  cent 
of  milk  solids.  When  milk  is  skimmed,  soured,  or  treated  so  as 
to  resemble  buttermilk,  it  should  be  known  by  some  distinctive 
name. 

Homogenized  Milk  or  Cream. 

The  commission  is  of  the  opinion  that  in  the  compounding  of 
milk  no  fats  other  than  milk  fats  from  the  milk  in  process  should 
be  used  and  that  no  substance  foreign  to  milk  should  be  added  to  it. 
The  commission  is  opposed  to  the  use  of  condensed  milk  or  other 
materials  for  the  thickening  of  cream  unless  the  facts  are  clearly 
set  forth  on  the  label  of  the  retail  package.  Regarding  the  process 
of  homogenizing,  the  commission  resolved  as  follows: 

That  homogenized  milk  or  cream  should  be  so  marked,  stating  the  percentage  of 
fat  that  it  contains. 

Adjusted  Milks. 

On  the  question  of  milks  and  creams  in  which  the  ratio  of  the 
fats  to  the  solids  not  fat  has  been  changed  by  the  addition  to  or 
subtraction  of  cream  or  milk  fat  the  commission  has  hesitated  to 
take  a  position.  On  the  one  hand  they  are  in  favor  of  every 
procedure  which  will  increase  the  market  for  good  milk  and  make 
the  most  profitable  use  of  every  portion  of  it.  On  the  other,  they 
recognize  the  sensitiveness  of  milk,  the  ease  with  which  it  is  con- 
taminated, and  the  difficulty  of  controlling,  standardizing,  skim- 
ming, homogenizing,  souring,  etc.,  so  that  contaminations^  do  not 
occur  and  inferior  materials  are  not  used.  On  this  subject  the 
commission  passed  a  resolution  presented  by  a  special  committee 
as  follows: 

Milk  in  which  the  ratio  of  the  fats  to  the  solids  not  fat  has  been  changed  by  the 
addition  to  or  subtraction  of  cream  should  be  labeled  "adjusted  milk";  the  label 
should  show  the  minimum  guaranteed  percentage  of  fat  and  should  comply  with  the 
same  sanitary  or  chemical  requirements  as  for  milk  not  so  standardi7ed  or  modified. 


244  Principles   of   Legislative   Milk    Control. 

Regulation  of  Market  Milk  on  Basis  of  Guaranteed  Percentage 

Composition. 

1.  Sellers  of  milk  should  be  permitted  choice  of  one  of  two 
systems  in  handling  market  milk.     Milk  can  be  sold,  first,  under 
the  regular  standard,  or,  second,  under  a  guaranteed  statement  of 
composition. 

2.  Any  normal  milk  may  be  sold  if  its  per  cent  of  fat  is 
stated.    In  case  the  per  cent  of  fat  is  not  stated,  the  sale  will  be 
regarded  as  a  violation  unless  the  milk  contains  at  least  3.25  per 
cent  of  milk  fat. 

3.  As  a  further  protection  to  consumers,  it  is  desirable  that 
when  the  guaranty   system   is  used  there  be   also   a  minimum 
guaranty  of  milk  solids  not  fat  of  not  less  than  8.5  per  cent. 

4.  Dealers  electing  to  sell  milk  under  the  guaranty  system 
should  be  required  to  state  conspicuously  the  guaranty  on  all  con- 
tainers in  which  such  milk  is  handled  by  the  dealer  or  delivered 
to  the  consumer. 

5.  The  sale  of  milk  on  a  guaranty  system  should  be  by  special 
permission  obtained  from  some  proper  local  authority. 

Penalty. 
Every  milk  ordinance  should  contain  a  penalty  clause. 

Extension  Work. 

The  commission  indorsed  the  efforts  of  the  New  York  Milk 
Committee  to  obtain  funds  for  the  formation  of  a  bureau  of  exten- 
sion work,  such  bureau  to  act  as  a  collecting  station  for  informa- 
tion regarding  standards  and  regulations  as  to  milk  adopted  by 
cities  and  towns  in  the  United  States.  The  bureau  should  also 
furnish  information  to  such  cities  and  towns  as  appeal  for  aid 
in  the  adoption  of  milk  standards  and  should  conduct  a  construct- 
ive program  by  placing  in  the  field  a  man  who  would  visit  com- 
munities interested  in  establishing  milk  standards;  and  it  may 
use  the  members  of  the  commission  on  milk  standards  for  carrying 
on  the  work  of  the  bureau  so  far  as  possible  in  their  own  localities. 

The  commission  has  confined  its  report  rather  closely  to  the 
standard  requirements  for  milk.  These  requirements  can  not  be 
met  unless  proper  measures  are  taken.  For  instance :  The  milk 
must  be  produced  from  healthy  cows  in  clean  surroundings,  and 
must  then  be  promptly  chilled  and  kept  cool  thereafter.  The  hand- 
ling at  all  points  must  be  done  by  healthy  employees — employees 
who  are  not  carriers  of  contagion. 

The  reports  of  the  subcommittees  on  the  methods  of  produc- 
tion, handling,  and  distribution,  while  not  properly  a  part  of  the 
report  itself,  are  set  forth  in  the  following  pages. 


Licenses   and   Permits   for   Dealers.  245 


STANDARD    RULES    FOR    THE    PRODUCTION,    HAN- 
DLING,   AND    DISTRIBUTION    OF    MILK. 

As  a  basis  for  the  promulgation  of  rules  and  recommendations 
governing  the  production,  handling,  and  distribution  of  milk,  it  is 
recognized  that  we  have  to  deal  with  two  kinds  of  milk,  raw  and 
pasteurized,  although  there  may  be  several  grades  of  each  of  these 
two  kinds.  In  order  for  any  grade  to  be  safe,  it  is  recommended 
that  the  regulations  herein  set  forth  under  the  heading  "Re- 
quirements" should  be  enforced.  The  regulations  herein  set  forth 
under  the  heading  "Recommendations"  should  be  adopted  wher- 
ever practicable  as  a  means  of  improving  the  milk  supply  above 
the  actual  point  of  safety.  (The  term  "milk"  shall  be  construed 
to  include  the  fluid  derivatives  of  milk  wherever  such  construction 
of  the  term  is  applicable.) 

LICENSES. 

Requirements. 

No  person  shall  engage  in  the  sale,  handling,  or  distribution 

of  milk  in until  he  has  obtained  a  license  therefor  from  the 

health  authorities.    This  license  shall  be  renewed  on  or  before  the 

1st  day  of of  each  year  and  may  be  suspended  or  revoked. at 

any  time  for  cause. 

Recommendations. 

The  application  for  the  license  shall  include  the  following  statements : 

(1)  Kind  of  milk  to  be  handled  or  sold. 

(2)  Names  of  producers  with  their  addresses  and  permit  numbers. 

(3)  Names  of  middlemen  with  their  addresses. 

(4)  Names  and  addresses  of  all  stores,  hotels,  factories,  and  restaurants  at  which 
milk  is  delivered. 

(5)  A  statement  of  the  approximate  number  of  quarts  of  milk,  cream,  buttermilk, 
and  skim  milk  sold  per  day. 

(6)  Source  of  water  supply  at  farms  and  bottling  plants. 

(7)  Permission  to  inspect  all  local  and  out-of-town  premises  on  which  milk  is 
produced  and  handled. 

(8)  Agreement  to  abide  by  all  the  provisions  of  State  and  local  regulations. 

PERMITS. 

Requirements. 

No  person  shall  engage  in  the  production  of  milk  for  sale  in 
nor  shall  any  person  engage  in  the  handling  of  milk  for 


shipment  into -  until  he  has  obtained  a  permit  therefor  from 

the  health  authorities.  This  permit  shall  be  renewed  on  or  before 
the  1st  day  of  -  -  of  each  year  and  may  be  suspended  or  re- 
voked at  any  time  for  cause. 


246  Principles   of   Legislative   Milk    Control. 

PRODUCTION   OF  RAW   MILK. 
Cow  Stables. 

Requirements. 

1.  They  shall  be  used  for  no  other  purpose  than  for  the  keep- 
ing of  cows,  and  shall  be  light,  well  ventilated,  and  clean. 

2.  They  shall  be  ceiled  overhead  if  there  is  a  loft  above. 

3.  The  floors  shall  be  tight  and  sound. 

4.  The  gutters  shall  be  water-tight. 

Recommendations. 

1.  The  window  area  shall  be  at  least  2  square  feet  per  500  cubic  feet  of  air  space 
and  shall  be  uniformly  distributed,  if  possible.     If  uniform  distribution  is  impossible, 
sufficient  additional  window  area  must  be  provided  so  that  all  portions  of  the  barn  shall 
be  adequately  lighted. 

2.  The  amount  of  air  space  shall  be  at  least  500  cubic  feet  per  cow,  and  adequate 
ventilation  besides  windows  shall  be  provided. 

3.  The  walls  and  ceilings  shall  be  whitewashed  at  least  once  every  six  months 
unless  the  construction  renders  it  unnecessary,  and  shall  be  kept  free  from  cobwebs  and 
dirt. 

4.  All  manure  shall  be  removed  at  least  twice  daily,  and  disposed  of  so  as  not  to  be 
a  source  of  danger  to  the  milk  either  as  furnishing  a  breeding  place  for  flies  or  otherwise. 

5.  Horse  manure  shall  not  be  used  in  the  cow  stable  for  any  purpose. 

Milk  Room. 
Requirements. 

Every  milk  farm  shall  be  provided  with  a  milk  room  that  is 
clean,  light,  and  well  screened.  It  shall  be  used  for  no  other  pur- 
pose than  for  the  cooling,  bottling,  and  storage  of  milk  and  the 
operations  incident  thereto. 

Recommendations. 

1.  It  shall  have  no  direct  connection  with  any  stable  or  dwelling. 

2.  The  floors  shall  be  of  cement  or  other  impervious  material,  properly  graded  and 
drained. 

3.  It  shall  be  provided  with  a  sterilizer  unless  the  milk  is  sent  to  a  bottling  plant, 
in  which  case  the  cans  shall  be  sterilized  at  the  plant. 

4.  Cooling  and  storage  tanks  shall  be  drained  and  cleaned  at  least  twice  each  week. 

5.  All  drains  shall  discharge  at  least  100  feet  from  any  milk  house  or  cow  stable. 

Cows. 

Requirements. 

1.  A  physical  examination  of  all  cows  shall  be  made  at  least 
once  every  six  months  by  a  veterinarian  approved  by  the  health 
authorities. 

2.  Every  diseased  cow  shall  be  removed  from  the  herd  at 
once  and  no  milk  from  such  cows  shall  be  offered  for  sale. 

3.  The  tuberculin  test  shall  be  applied  at  least  once  a  year  by 
a  veterinarian  approved  by  the  health  authorities. 


Standards    for   Raw    Milk.  247 

4.  All  cows  which  react  shall  be  removed  from  the  herd  at 
once,  and  no  milk  from  such  cows  shall  be  sold  as  raw  milk. 

5.  No  new  cows  shall  be  added  to  a  herd  until  they  have 
passed  a  physical  examination  and  the  tuberculin  test. 

6.  Cows,  especially  the  udders,  shall  be  clean  at  the  time  of 
milking. 

7.  No  milk  that  is  obtained  from  a  cow  within  15  days  before 
or  5  days  after  parturition,  nor  any  milk  that  has  an  unnatural 
odor  or  appearance,  shall  be  sold. 

8.  No  unwholesome  food  shall  be  used. 

Recommendations. 

1.  Every  producer  shall  allow  a  veterinarian  employed  by  the  health  authorities 
to  examine  his  herd  at  any  time  under  the  penalty  of  having  his  supply  excluded. 

2.  Certificates  showing  the  results  of  all  examinations  shall  be  filed  with  the  health 
authorities  within  10  days  of  such  examinations. 

3.  The  tuberculin  tests  shall  be  applied  at  least  once  every  six  months  by  a  veteri- 
narian approved  by  the  health  authorities,  unless  on  the  last  previous  test  no  tubercu- 
losis was  present  in  the  herd  or  in  the  herds  from  which  new  cows  were  obtained,  in  which 
event  the  test  may  be  postponed  an  additional  six  months. 

4.  Charts  showing  the  results  of  all  tuberculin  tests  shall  be  filed  with  the  health 
authorities  within  10  days  of  the  date  of  such  test. 

5.  The  udders  shall  be  washed  and  wiped  before  milking. 

Employees. 

Requirements. 

1.  All  employees  connected  in  any  way  with  the  production 
and  handling  of  milk  shall  be  personally  clean  and  shall  wear 
clean  outer  garments. 

2.  The  health  authorities  shall  be  notified  at  once  of  any 
communicable  disease  in  any  person  that  is  in  any  way  connected 
with  the  production  or  handling  of  milk,  or  of  the  exposure  of 
such  person  to  any  communicable  disease. 

3.  Milking  shall  be  done  only  with  dry  hands. 

Recommendations. 

1.  Clean  suits  shall  be  put  on  immediately  before  milking. 

2.  The  hands  shall  be  washed  immediately  before  milking  each  cow,  in  order  to 
avoid  conveyance  of  infection  to  the  milk. 

Utensils. 

Requirements. 

1.  All  utensils  and  apparatus  with  which  milk  comes  in  con- 
tact shall  be  thoroughly  washed  and  sterilized,  and  no  milk  utensils 
or  apparatus  shall  be  used  for  any  other  purpose  than  that  for 
which  it  was  designed. 

2.  The  owner's  name,  license  number,  or  other  identification 
mark,  the  nature  of  which  shall  be  made  known  to  the  health 


248  Principles   of   Legislative   Milk    Control. 

authorities,  shall  appear  in  a  conspicuous  place  on  every  milk 
container. 

3.  No  bottle  or  can  shall  be  removed  from  a  house  in  which 
there  is,  or  in  which  there  has  recently  been,  a  case  of  communi- 
cable disease  until  permission  in  writing  has  been  granted  by  the 
health  authorities. 

4.  All  metal  containers  and  piping  shall  be  in  good  condi- 
tion at  all  times.     All  piping  shall  be  sanitary  milk  piping,  in 
couples  short  enough  to  be  taken  apart  and  cleaned  with  a  brush. 

5.  Small-top  milking  pails  shall  be  used. 

Recommendations. 

1.  All  cans  and  bottles  shall  be  cleaned  as  soon  as  possible  after  being  emptied. 

2.  Every  conveyance  used  for  transportation  or  delivery  of  milk,  public  carriers 
excepted,  shall  bear  the  owner's  name,  milk-license  number,  and  business  address  in  un- 
condensed  gothic  characters  at  least  2  inches  in  height. 

Handling  of  Milk. 

Requirements. 

1.  It  shall  not  be  strained  in  the  cow  stable,  but  shall  be 
removed  to  the  milk  room  as  soon  as  it  is  drawn  from  the  cow. 

2.  It  shall  be  cooled  to  50°  F.  or  below  within  two  hours 
after  it  is  drawn  from  the  cow  and  it  shall  be  kept  cold  until  it  is 
delivered  to  the  consumer. 

3.  It  shall  not  be  adulterated  by  the  addition  to  or  the  sub- 
traction of  any  substance  or  compound,  except  for  the  production 
of  the  fluid  derivatives  allowed  by  law. 

4.  It  shall  not  be  tested  by  taste  at  any  bottling  plant,  milk 
house,  or  other  place  in  any  way  that  may  render  it  liable  to 
contamination. 

5.  It  shall  be  bottled  only  in  a  milk  room  or  bottling  plant  for 
which  a  license  or  permit  has  been  issued. 

6.  It  shall  be  delivered  in  bottles,  or  single  service  containers, 
with  the  exception  that  20  quarts  or  more  may  be  delivered  in  bulk 
in  the  following  cases : 

(a)  To  establishments  in  which  milk  is  to  be  consumed  or 
used  on  the  premises. 

(b)  To   infant-feeding  stations   that   are  under   competent 
medical  supervision. 

7.  It  shall  not  be  stored  in  or  sold  from  a  living  room  or  from 
any  other  place  which  might  render  it  liable  to  contamination. 

Recommendations. 

1.  It  shall  be  cooled  to  50°  F.  or  below  immediately  after  milking  and  shall  be 
kept  at  or  below  that  temperature  until  it  is  delivered  to  the  consumer. 

2.  It  shall  contain  no  visible  foreign  material. 

3.  It  shall  be  labeled  with  the  date  of  production. 


Standards    for   Raw   Milk.  249 


Receiving  Stations  and  Bottling  Plants. 

Requirements. 

1.  They  shall  be  clean,  well  screened,  and  lighted,  and  shall 
be  used  for  no  other  purpose  than  the  proper  handling  of  milk 
and  the  operations  incident  thereto,  and  shall  be  open  to  inspec- 
tion by  the  health  authorities  at  any  time. 

2.  They    shall    have    smooth,    impervious    floors,    properly 
graded  and  drained. 

3.  They  shall  be  equipped  with  hot  and  cold  water  and  steam. 

4.  Ample  provision  shall  be  made  for  steam  sterilization  of 
all  utensils,  and  no  empty  milk  containers  shall  be  sent  out  until 
after  such  sterilization. 

5.  All  utensils,  piping,  and  tanks  shall  be  kept  clean  and 
shall  be  sterilized  daily. 

Recommendations. 

1.     Containers  and  utensils  shall  not  be  washed  in  the  same  room  in  which  milk  is 
handled. 

Stores. 

Requirements. 

1.  All  stores  in  which  milk  is  handled  shall  be  provided  with 
a  suitable  room  or  compartment  in  which  the  milk  shall  be  kept. 
Said  compartment  shall  be  clean  and  shall  be  so  arranged  that  the 
milk  will  not  be  liable  to  contamination  of  any  kind. 

2.  Milk  shall  be  kept  at  a  temperature  not  exceeding  50°  F. 

Recommendations. 

1.     Milk  to  be  consumed  off  the  premises  may  be  sold  from  stores  only  in  the 
original  unopened  package. 

General  Regulations. 
Requirements. 

1.  The  United  States  Bureau  of  Animal  Industry  score  card 
shall  be  used,  and  it  is  recommended  that  dairies  from  which  milk 
is  to  be  sold  in  a  raw  state  shall  score  at  least  80  points. 

2.  Every  place  where  milk  is  produced  or  handled  and  every 
conveyance  used  for  the  transportation  of  milk  shall  be  clean. 

3.  All  water  supplies  shall  be  from  uncontaminated  sources 
and  from  sources  not  liable  to  become  contaminated. 

4.  The  license  or  permit  shall  be  kept  posted  in  a  conspicuous 
place  in  every  establishment  for  the  operation  of  which  a  milk 
license  or  permit  is  required. 

5.  No  milk  license  or  permit  shall  at  any  time  be  used  by  any 
person  other  than  the  one  to  whom  it  was  granted. 


250  Principles   of   Legislative   Milk    Control. 

6.  No  place  for  the  operation  of  which  a  license  or  permit  is 
granted  shall  be  located  within  100  feet  of  a  privy  or  other  possible 
source  of  contamination,  nor  shall  it  contain  or  open  into  a  room 
which  contains  a  water-closet. 

7.  No  skim  milk  or  buttermilk  shall  be  stored  in  or  sold  from 
cans  or  other  containers  unless  such  containers  are  of  a  distinctive 
color  and  permanently  and  conspicuously  labeled  "skim  milk"  or 
"buttermilk,"  as  the  case  may  be. 

8.  No  container  shall  be  used  for  any  other  purpose  than 
that  for  which  it  is  labeled. 

Recommendations. 

1.  Ice  used  for  cooling  purposes  shall  be  clean  and  uncontaminated. 

2.  No  person  whose  presence  is  not  required  shall  be  permitted  to  remain  in  any 
cow  stable,  milk  house,  or  bottling  room. 

SUBNORMAL  MILK. 

Requirements. 

1.  Natural  milk  that  contains  less  than  3.25  per  cent,  but 
more  than  2.5  per  cent  milk  fat,  and  that  complies  in  all  other 
respects  with  the  requirements  above  set  forth,  may  be  sold,  pro- 
vided the  percentage  of  fat  does  not  fall  below  a  definite  percent- 
age that  is  stated  in  a  conspicuous  manner  on  the  container ;  and 
further  provided  that  such  container  is  conspicuously  marked 
"substandard  milk." 

PRODUCTION   OF    CREAM. 

Requirements  and  Recommendations. 

1.  It  shall  be  obtained  from  milk  that  is  produced  and 
handled  in  accordance  with  the  provisions  hereinbefore  set  forth 
for  the  production  and  handling  of  milk. 

LABORATORY  STANDARDS  FOR  MILK. 

Requirements. 

1.  It  shall  not  contain  more  than  100,000  bacteria  per  cubic 
centimeter. 

2.  It  shall  contain  not  less  than  3.25  per  cent  milk  fat. 

3.  It  shall  contain  not  less  than  8.5    per  cent  solids  not  fat. 

Recommendations. 

1.     The  bacterial  limit  shall  be  lowered  if  possible. 

LABORATORY  STANDARDS  FOR  CREAM. 

Requirements. 

1.  There  shall  be  a  bacterial  standard  for  cream  correspond- 
ing to  the  grade  of  milk  from  which  it  is  made  and  to  its  butter-fat 
content. 

2.  It  shall  contain  not  less  than  18  per  cent,  milk  fat, 

Recommendations. 

Same  as  above  for  milk. 


Principles   of   Legislative   Milk    Control. 


251 


SANITARY   INSPECTION   OF    CITY   MILK   PLANTS 


SCORE    CARD. 

Owner  or  manager: —     — .     Street  and  No. :- 

Trade   name: .     Number   of   wagons: 

Cream: —     — .     Permit  or  License  No.: 

Eemarks : . 


City:- 


-.     State  :- 
Gallons   sold   daily — Milk:- 


Date  of  Inspection :- 


191. 


Equipment. 

Score. 

Methods. 

Score. 

Perfect 

Allowed 

Perfect  Allowed 

Building: 
Location:    Free    from    contami- 

2 

7 

12 
15 

2 
2 

< 

Building     

14 
7 

7 
22 

6 
4 

Cleanliness: 
Floors     3 

Walls    2 

Separate  receiving  room.  .  .    1 
Separate  handling  room...    2 

' 

Ceilings    2 

Doors  and  windows  1 

Shafting,  pulleys,  pipes,  etc.  1 
Freedom  from  odors  2 
Freedom  from  flies   3 

Separate  boiler  room  1 
Separate  refrigerator  room.    1 

Cleanliness: 
Thoroughly       washed      and 
rinsed     3 

Floors  tight,  sound,  cleanable   2 
Walls  tight,  smooth,  clean  'ble   1 
Ceiling   smooth,    tight,    clean- 
able            1 

Milk-handling       machin- 

Sterilized  with  live  steam.  .    3 
Milk-handling      machin- 

Sewer  or  septic  tank...    1 

(10  per  cent  of  floor  space.) 
Provision  for  pure  air  2 

Protected    from    contamina- 

Minimum    of    shafting,    pul- 
leys,       hangers,        exposed 

Bottles    

Thoroughly        washed        and 

Sterilized  with  steam  15  min- 
utes                  .           3 

Boiler  2 

(Water  heater,   1.) 
Appliances       for       cleansing 

Inverted  in  clean  place  1 

Received  below  50°  F                 3 

') 
I 

Sterilizers  for  bottles,  etc.  .  .    2 

(50°  to  55°,  2)  ;  (55°  to  60°,1.) 

Freedom   from  undue   expos- 
ure to  air    2 

Wash  bowl,   soap,   and  towel 
in  handling  room  1 

Condition     6 

Promptness     2 

Milk-handling    machinery    3 
Pipes,       couplings,       and 

DUlllDS      .                                           .     2 

Below  45°  F               3 

(45°  to  50°,  1.) 
Capping  bottles  by  machine.    2 
Bottle  top  protected  by  cover   1 

Cans   1 

(45°  to  50°,  3;  50°  to  55°,  1.) 
Protection  during  delivery.  .    2 
(Iced   in    summer.) 

Convenient  and  abundant.  .  .    1 
Total                           

Inspection  of  dairies  supply- 

(2  times  a  year,  2;  once  a 
year,   1.) 

Cleanliness   of   attendants...    2 
Personal  cleanliness   1 
Clean,  washable  clothing.  .  .    1 
Cleanliness  of  delivery  outfit   2 

Total    

40 

60 

Score  of  equipment -f-    Score   for  Methods =   Total   Score. 

NOTE. — If  the  conditions  in  any  particular  are  so  exceptionally  bad  as  to  be  inadequately  ex- 
pressed by  a  score  of   "0"   the  inspector  can   make  a  deduction  from  the  total  score. 

[C'ir.  199]  ,  Inspector. 


252 


Score    Card    for   Dairy   Farms. 


SANITARY  INSPECTION   OF   DAIRY  FARMS 

SCORE   CARD. 

Indorsed  by  the  Official  Dairy  Instructor's  Association. 

Owner  or  lessee  of  farm:  .     P.  O.  address:  —        — .     State: 

Total  number  of  cows: .     Number  milking:  —    — .     Gallons  of  milk  produced 

daily:  .     Product  is  sold  by  producer  in  families,  hotels,  restaurants,  stores,  to 


-dealer.     For  milk  supply  of 
Eemarks:  . 


Permit  No. 


(Signed) 


Date  of  inspection. 
Inspector. 


Equipment 

Score. 

Methods. 

Score. 

Perfect 

Allowed 

Perfect|Allowed 

Cows. 
Health    

6 

1 
1 

2 
4 

4 

1 

7 

1 
1 

5 
1 
1 

1 

2 

1 

1 

Cows. 

8 
6 

5 

1 
2 

2 
3 

8 

9 

2 

2 

2 
5 

2 

Apparently  in  good  health..    1 
If     tested     with     tuberculin 
within  a  year  and  no  tuber- 
culosis is  found,  or  if  tested 
within    six    months    and    all 
reacting    animals    removed.    5 
(If  tested  within  a  year  and 
reacting   animals   are   found 
and  removed,   3.) 
Food   (clean  and  wholesome)... 

(Free  from  visible  dirt,  6.) 
Stables. 
Cleanliness  of  stables  

Floor    2 

Walls  1 

Ceiling  and  ledges   1 

Mangers    and    partitions.  ...    1 
Windows    1 

Stables. 

Stable  air  at  milking  time  
Freedom   from   dust    3 

1 

Freedom   from   odors  2 

Cleanliness   of   bedding  

Free  from  contaminating  sur- 

Barnyard      

Clean   1 

aings     i 

Well    drained    1 

Tight,  sound  floor  and  proper 

Removal  of  manure  daily  to  50 
feet  from  stable  

Smooth,  tight  walls  and  ceil- 
ing        1 

Milk  Room  or  Milk  House. 
Cleanliness  of  milk  room  

Proper  stall,  tie,  and  manger   1 
Provision  for  light:  Four  sq.  ft., 
of  glass  per  cow    

Utensils    and    Milking. 
Care  and  cleanliness  of  utensils 
Thoroughly   wasned    2 

(Three  sq.  ft.,  3  ;  2  sq.  ft.,  2; 

1  sq.  ft.,  1.     Deduct  for  un- 
even  distribution.) 
Bedding     

Sterlized    in    steam    for    15 
minutes    3 
(Places  over  steam  jet,  or 
scalded        with        boiling 
water,  2.) 
Protected     from     contamina- 
tion         3 

Ventilation    

Provision  for  fresh  air,  con- 
trollable flue  system  3 

(Windows   hinged   at   bot- 
tom,    1.5;     sliding     win- 
dows,  1  ;   other  openings, 
0.5.) 
Cubic  feet  of  space  per  cow 
500  ft  

Clean,   dry  hands    3 

1 

Udders  washed  and  wiped.  .    6 
(Udders    cleaned    with    moist 
cloth,    4;    cleaned    with    dry 
cloth    or    brush    at    least    15 
minutes   before   milking,    1.) 

Handling   the    Milk. 
Cleanliness      of      attendants     in 
milk  room   

(Less  than  500  ft.,  2;  less 
than  400  ft.,  1;  less  than 
300  ft.,   0.) 
Provision       for       controlling 
temperature     1 

Utensils. 
Construction    and    condition    of 
utensils    

Milk  removed  immediately  from 
stable     without     pouring     from 

\Vater   for   cleaning    

(Clean,    convenient,    and   abun- 
dant.) 
Small-top   milking  pail  

I 

Cooled    immediately    after   milk- 
ing each   cow    

Milk  cooler   
Clean    milking    suits    

(51°  to  55°,  4;  56°  to  60°,  2.) 

Milk  Room  or  Milk  House. 
Location:  Free  from  contaminat- 
ing  surroundings    

(51°  to  55°,  2;  56°  to  60°,  1.) 
Transportation  below  50°  F... 
(51°  to  55°.  1.5  ;56°  to  60°,  1.) 
(If  delivered  twice  a  day,   al-  ' 
low   perfect    score    for    storage 
and  transportation.) 

Total    

Construction   of  milk   room  
Floor,  walls,  and  ceiling.  ...    1 
Light,  ventilation,  screens.  .  .    1 
Separate      rooms      for     washing 
utensils  and  handling  milk   .  .  . 

(Hot   water,  0.5.) 
Total    

40 

60 

Equipment +    Methods =    Final    Score. 

NOTE   1. — If  any  exceptionally  filthy  condition  is   found,  particularly  dirty  utensils,   the  total 
score  may  be  further  limited. 

NOTE  2. — If  the  water  is  exposed  to  dangerous  contamination,  or  there  is  evidence  of  the  pres- 
ence of  a  dangerous  disease  in  animals  or  attendants,  the  score  shall  be  0. 
[Cir.    199  J 


Standards    for   Pasteurized    Milk.  253 


STANDARDS  FOR  SKIM  MILK. 

Requirements. 

1.  It  shall  contain  not  less  than  8.75  per  cent  milk  solids. 

2.  Control  of  sale  of  skim  milk :    Whether  skim  milk  is  sold 
in  wagons  or  in  stores  all  containers  holding  skim  milk  should  be 
painted  some  bright,  distinctive  color  and  prominently  and  legibly 
marked  "skim  milk."    When  skim  milk  is  placed  in  the  buyer's 
container,  a  label  or  tag  bearing  the  words  "skim  milk"  should 
be  attached. 

PRODUCTION   OF   PASTEURIZED   MILK 

Pasteurized  milk  is  milk  that  is  heated  to  a  temperature  of 
not  less  than  140°  F.  for  not  less  than  20  minutes,  or  not  over 
155°  F.  for  not  less  than  5  minutes,  and  for  each  degree  of  tem- 
perature over  140°  F.  the  length  of  time  may  be  1  minute  less 
than  20.  Said  milk  shall  be  cooled  immediately  to  50°  F.  or  below 
and  kept  at  or  below  that  temperature. 

Cow  Stables. 

Requirements. 
The  same  as  for  the  production  of  raw  milk. 

Recommendations. 

The  same  as  for  the  production  of  raw  milk. 

Milk  Room. 

Requirements. 
The  same  as  for  the  production  of  raw  milk. 

Recommendations. 

The  same  as  for  the  production  of  raw  milk. 

Cows. 

Requirements. 

The  same  as  for  the  production  of  raw  milk,  with  the  excep- 
tion of  the  sections  relating  to  the  tuberculin  test. 

Recommendations. 

That  no  cows  be  added  to  a  herd  excepting  those  found  to  be  free  from  tuberculosis 
by  the  tuberculin  test. 

Employees. 

Requirements. 
The  same  as  for  the  production  of  raw  milk. 


254  Principles   of   Legislative   Milk    Control. 

Recommendations. 

The  same  as  for  the  production  of  raw  milk. 

Utensils. 

Requirements. 
The  same  as  for  the  production  of  raw  milk. 

Recommendations. 

The  same  as  for  the  production  of  raw  milk. 

Milk  for  Pasteurization. 

Requirements. 

1.  The  same  as  for  the  production  of  raw  milk,  with  the  ex- 
ception of  sections  1,  2,  and  6b. 

2.  It  shall  be  cooled  to  60°  P.     or  below  within  two  hours 
after  it  is  drawn  from  the  cow,  and  it  shall  be  held  at  or  below 
that  temperature  until  it  is  pasteurized.    After  pasteurization,  it 
shall  be  held  at  a  temperature  not  exceeding  50°  F.  until  delivered 
to  the  consumer. 

3.  Pasteurized  milk  shall  be  distinctly  labeled  as  such,  to- 
gether with  the  temperature  at  which  it  is  pasteurized  and  the 
shortest  length  of  exposure  to  that  temperature  and  the  date  of 
pasteurization. 

Recommendations. 

1.  No  milk  shall  be  repasteurized. 

2.  The   requirements   governing  the   production   and  handling  of  milk   for  pas- 
teurization should  be  raised  wherever  practicable. 

Pasteurizing  Plants. 

Requirements. 

The  same  as  under  ''Receiving  stations  and  bottling  plants" 
for  raw  milk. 

Recommendations. 

The  same  as  under  ' '  Keceiving  stations  and  bottling  plants ' '  for  raw  milk. 

Stores. 

Requirements. 
The  same  as  for  raw  milk. 

Recommendations. 

The  same  as  for  raw  milk. 


Standards    for    Pasteurized    Milk.  255 


General  Regulations. 
Requirements. 

1.  It  is  recommended  that  dairies  producing  milk  which  is 
to  be  pasteurized  shall  be  scored  on  the  United  States  Bureau  of 
Animal  Industry  score  card,  and  that  health  departments,  or  the 
controlling  departments  whatever  they  may  be,  strive 'to  bring 
these  scores  up  as  rapidly  as  possible. 

2.  Milk  from  cows  that  have  been  rejected  by  the  tuberculin 
test,  but  which  show  no  physical  signs  of  tuberculosis,  as  well  as 
those  which  have  not  been  tested,  may  be  sold  provided  that  it  is 
produced  and  handled  in  accordance  with  all  the  other  require- 
ments herein  set  forth  for  pasteurized  milk. 

3.  Ice  used  for  cooling  purposes  shall  be  clean. 

Recommendations. 

The  same  as  for  raw  milk. 

PRODUCTION   OF   PASTEURIZED   CREAM. 

Requirements. 

1.  It  shall  be  obtained  only  from  milk  that  could  legally  be 
sold  as  milk  under  the  requirements  hereinbefore  set  forth. 

2.  Pasteurized  cream,  or  cream  separated  from  pasteurized 
milk,  shall  be  labeled  in  the  manner  herein  provided  for  the  label- 
ing of  pasteurized  milk. 

STANDARDS   FOR   PASTEURIZED   MILK. 

Requirements. 

1.  It  shall  not  contain  more  than  1,000,000  bacteria  per  cubic 
centimeter  before  pasteurization,  nor  over  50,000  when  delivered 
to  the  consumer. 

2.  The  standards  for  the  percentage  of  milk  fat  and  of  total 
solids  shall  be  the  same  as  for  raw  milk. 

Recommendations. 

1.  The  limits  for  the  bacterial  count  before  pasteurization  and  after  pasteurization 
should  both  be  lowered  if  possible. 

STANDARDS  FOR  PASTEURIZED  CREAM. 

Requirements. 

1.  No  cream  shall  be  sold  that  is  obtained  from  pasteurized 
milk  that  could  not  be  legally  sold  under  the  provisions  herein  set 
forth,  nor  shall  any  cream  that  is  pasteurized  after  separation 
contain  an  excessive  number  of  bacteria. 


256  Principles   of   Legislative   Milk    Control. 

2.  There  shall  be  a  bacterial  standard  for  pasteurized  cream 
corresponding  to  the  grade  of  milk  from  which  it  is  made  and  to 
its  butterfat  content. 

3.  The  percentage  of  milk  fat  shall  be  the  same  as  for  raw 
cream. 

SANITARY  INSPECTION  OF  MILK  PLANTS  AND  DAIRY  FARMS. 

Blank  forms  of  the  latest  United  States  Bureau  of  Animal 
Industry  score  cards  which  have  been  previously  referred  to,  are 
shown  on  pages  251-252.  Experience  has  shown  that  there  is  no 
system. of  sanitary  inspection  so  efficient  as  that  obtained  by  the  use 
of  these  cards.  Every  condition  pertaining  to  the  milk  is  considered 
and  rated  mathematically  according  to  its  importance.  The  com- 
pleted score  gives  an  accurate  survey  of  the  facts  in  a  comparative 
manner  which  may  serve  as  a  permanent  record,  far  more  reliable 
in  character  than  is  a  mere  inspection  unaided  by  the  score  card. 
This  system  not  only  provides  a  uniform  and  systematic  summary, 
but  it  also  has  a  tendency  to  stimulate  the  producer  to  increased 
efforts  in  overcoming  the  defects  which  reduce  his  total  score. 

PRODUCTION   OF  AND   STANDARDS  FOR  CERTIFIED  MILK. 

The  methods  and  standards  for  the  production  and  distribu- 
tion of  certified  milk,  adopted  by  the  American  Association  of 
Medical  Milk  Commissions,  May  1,  1912,  contain  all  the  necessary 
provisions  for  the  preparation  of  this  special  milk  which  undoubt- 
edly leads  all  classes  of  milk  as  a  food  for  infants. 

Hygiene  of  the  Dairy. 

UNDER    THE    SUPERVISION    AND    CONTROL    OF     THE    VETERINARIAN. 

1.  Pastures  or  paddocks. — Pastures  or  paddocks  to  which 
the  cows  have  access  shall  be  free  from  marshes  or  stagnant  pools, 
crossed  by  no  stream  which  might  become  dangerously  contami- 
nated, at  sufficient  distances  from  offensive  conditions  to  suffer 
no  bad  effects  from  them,  and  shall  be  free  from  plants  which 
affect  the  milk  deleteriously. 

2.  Surroundings    of    "buildings. — The    surroundings    of    all 
buildings  shall  be  kept  clean  and  free  from  accumulations  of  dirt, 
rubbish,  decayed  vegetable  or  animal  matter  or  animal  waste,  and 
the  stable  yard  shall  be  well  drained. 

3.  Location  of  buildings. — Buildings  in  which  certified  milk 
is  produced  and  handled  shall  be  so  located  as  to  insure  proper 
shelter  and  good  drainage,  and  at  sufficient  distance  from  other 
buildings,  dusty  roads,  cultivated  and  dusty  fields,  and  all  other 
possible  sources  of  contamination;  provided,  in  the  case  of  un- 
avoidable proximity  to  dusty  roads  or  fields,  the  exposed  side 
shall  be  screened  with  cheesecloth. 


Standards    for    Certified    Milk.  257 

4.  Construction  of  stables. — The  stables  shall  be  constructed 
so  as  to  facilitate  the  prompt  and  easy  removal  of  waste  products. 
The  floors  and  platforms  shall  be  made  of  cement  or  other  non- 
absorbent  material  and  the  gutters  of  cement  only.     The  floors 
shall  be  properly  graded  and  drained,  and  the  manure  gutters 
shall  be  from  6  to  8  inches  deep  and  so  placed  in  relation  to  the 
platform  that  all  manure  will  drop  into  them. 

5.  The  inside  surface  of  the  walls  and  all  interior  construc- 
tion shall  be  smooth,  with  tight  joints,  and  shall  be  capable  of 
shedding  water.    The  ceiling  shall  be  of  smooth  material  and  dust 
tight.    All  horizontal  and  slanting  surfaces  which  might  harbor 
dust  shall  be  avoided. 

6.  Drinking  and  feed  troughs. — Drinking  troughs  or  basins 
shall  be  drained  and  cleaned  each  day,  and  feed  troughs  and  mix- 
ing floors  shall  be  kept  in  a  clean  and  sanitary  condition. 

7.  Stanchions. — Stanchions,  when  used,  shall  be  constructed 
of  iron  pipes  or  hardwood,  and  throat  latches  shall  be  provided 
to  prevent  the  cows  from  lying  down  between  the  time  of  cleaning 
and  the  time  of  milking. 

8.  Ventilation. — The  cow  stables  shall  be  provided  with  ade- 
quate ventilation  either  by  means  of  some  approved  artificial  de- 
vice, or  by  the  substitution  of  cheesecloth  for  glass  in  the  windows, 
each  cow  to  be  provided  with  a  minimum  of  600  cubic  feet  of  air 
space. 

9.  Windows. — A  sufficient  number  of  windows  shall  be  in- 
stalled and  so  distributed  as  to  provide  satisfactory  light  and  a 
maximum  of  sunshine,  2  feet  square  of  window  area  to  each  600 
cubic  feet  of  air  space  to  represent  the  minimum.    The  coverings 
of  such  windows  shall  be  kept  free  from  dust  and  dirt. 

10.  Exclusion  of  flies,  etc. — All  necessary  measures  should 
be  taken  to  prevent  the  entrance  of  flies  and  other  insects  and 
rats  and  other  vermin  into  all  the  buildings. 

11.  Exclusion  of  animals  from  the  herd. — No  horses,  hogs, 
dogs,  or  other  animals  or  fowls  shall  be  allowed  to  come  in  contact 
with  the  certified  herd,  either  in  the  stables  or  elsewhere. 

12.  Bedding. — No  dusty  or  moldy  hay  or  straw,  bedding  from 
horse  stalls,  or  other  unclean  materials  shall  be  used  for  bedding 
the  cows.     Only  bedding  which  is  clean,  dry,  and  absorbent  may 
be  used,  preferably  shavings  or  straw. 

13.  Cleaning  stable  and  disposal  of  manure. — Soiled  bedding 
and  manure  shall  be  removed  at  least  twice  daily,  and  the  floors 
shall  be  swept  and  kept  free  from  refuse.    Such  cleaning  shall  be 
done  at  least  one  hour  before  the  milking  time.     Manure,  when 
removed,  shall  be  drawn  to  the  field  or  temporarily  stored  in  con- 
tainers so  screened  as  to  exclude  flies.    Manure  shall  not  be  even 
temporarily  stored  within  300  feet  of  the  barn  or  dairy  building. 

14.  Cleaning  of  cows. — Each  cow  in  the  herd  shall  be  groomed 
daily,  and  no  manure,  mud,  or  filth  shall  be  allowed  to  remain 

17 


258  Principles   of   Legislative   Milk    Control. 

upon  her  during  milking;  for  cleaning,  a  vacuum  apparatus  is 
recommended. 

15.  Clipping. — Long  hairs  shall  be  clipped  from  the  udder 
and  flanks  of  the  cow  and  from  the  tail  above  the  brush.    The  hair 
on  the  tail  shall  be  cut  so  that  the  brush  may  be  well  above  the 
ground. 

16.  Cleaning  of  udders. — The  udders  and  teats  of  the  cow 
shall  be  cleaned  before  milking;  they  shall  be  washed  with  a  cloth 
and  water,  and  dry  wiped  with  another  clean  sterilized  cloth — a 
separate  cloth  for  drying  each  cow. 

1.7.  Feeding. — All  foodstuffs  shall  be  kept  in  an  apartment 
separate  from  and  not  directly  communicating  with  the  cow  barn. 
They  shall  be  brought  into  the  barn  only  immediately  before  the 
feeding  hour,  which  shall  follow  the  milking. 

18.  Only  those  foods  shall  be  used  which  consist  of  fresh, 
palatable,   or  nutritious  materials,   such  as  will  not  injure   the 
health  of  the  cows  or  unfavorably  affect  the  taste  or  character 
of  the  milk.    Any  dirty  or  moldy  food  or  food  in  a  state  of  de- 
composition or  putrefaction  shall  not  be  given. 

19.  A  well-balanced  ration  shall  be  used,  and  all  changes  of 
food  shall  be  made  slowly.    The  first  few  feedings  of  grass,  alfalfa, 
ensilage,  green  corn,  or  other  green  feeds  shall  be  given  in  small 
rations  and  increased  gradually  to  full  ration. 

20.  Exercise. — All  dairy  cows  shall  be  turned  out  for  exer- 
cise at  least  2  hours  in  each  24  in  suitable  weather.     Exercise 
yards  shall  be  kept  free  from  manure  and  other  filth. 

21.  Washing  of  hands. — Conveniently  located  facilities  shall 
be  provided  for  the  milkers  to  wash  in  before  and  during  milking. 

22.  The  hands  of  the  milkers  shall  be  thoroughly  washed 
with  soap,  water,  and  brush  and  carefully  dried  on  a  clean  towel 
immediately  before  milking.     The  hands  of  the  milkers  shall  be 
rinsed  with  clean  water  and  carefully  dried  before  milking  each 
cow.    The  practice  of  moistening  the  hands  with  milk  is  forbidden. 

23.  Milking  clothes. — Clean  overalls,  jumper,  and  cap  shall 
be  worn  during  milking.    They  shall  be  washed  or  sterilized  each 
day  and  used  for  no  other  purpose,  and  when  not  in  use  they 
shall  be  kept  in  a  clean  place,  protected  from  dust  and  dirt. 

24.  Things  to  be  avoided  by  milkers. — While  engaged  about 
the  dairy  or  in  handling  the  milk  employees  shall  not  use  tobacco 
nor  intoxicating  liquors.    They  shall  keep  their  fingers  away  from 
their  nose  and  mouth,  and  no  milker  shall  permit  his   hands, 
fingers,  lips,  or  tongue  to  come  in  contact  with  milk  intended  for 
sale. 

25.  During  milking  the  milkers  shall  be  careful  not  to  touch 
anything  but  the  clean  top  of  the  milking  stool,  the  milk  pail,  and 
the  cow's  teats. 

26.  Milkers  are  forbidden  to  spit  upon  the  walls  or  floors 


Standards    for    Certified    Milk.  259 

of  stables,  or  upon  the  walls  or  floors  of  milk  houses,  or  into  the 
water  used  for  cooling  the  milk  or  washing  the  utensils. 

27.  Fore  milk. — The  first  streams  from  each  teat  shall  be 
rejected,  as  this  fore  milk  contains  large  numbers  of  bacteria. 
Such  milk  shall  be  collected  into  a  separate  vessel  and  not  milked 
onto  the  floors  or  into  the  gutters.     The  milking  shall  be  done 
rapidly  and  quietly,  and  the  cows  shall  be  treated  kindly. 

28.  Milk  and  calving  period. — Milk  from  all  cows  shall  be  ex- 
cluded for  a  period  of  45  days  before  and  7  days  after  parturition. 

29.  Bloody   and   stringy   milk. — If  milk  from   any  cow  is 
bloody  and  stringy  or  of  unnatural  appearance,  the  milk  from 
that  cow  shall  be  rejected  and  the  cow  isolated  from  the  herd 
until  the  cause  of  such  abnormal  appearance  has  been  determined 
and  removed,  special  attention  being  given  in  the  meantime  to 
the  feeding  or  to  possible  injuries.    If  dirt  gets  into  the  pail,  the 
milk  shall  be  discarded  and  the  pail  washed  before  it  is  used. 

30.  Make-up  of  herd. — No  cows  except  those  receiving  the 
same  supervision  and  care  as  the  certified  herd  shall  be  kept  in 
the  same  barn  or  brought  in  contact  with  them. 

31.  Employees  other  than  milkers. — The  requirements  for 
milkers,  relative  to  garments  and  cleaning  of  hands,  shall  apply 
to  all  other  persons  handling  the  milk,  and  children  unattended  by 
adults  shall  not  be  allowed  in  the  dairy  nor  in  the  stable  during 
milking. 

32.  Straining   and   strainers. — Promptly   after  the  milk  is 
drawn  it  shall  be  removed  from  the  stable  to  a  clean  room  and 
then  emptied  from  the  milk  pail  to  the  can,  being  strained  through 
strainers  made  of  a  double  layer  of  finely  meshed  cheesecloth  or 
absorbent  cotton  thoroughly  sterilized.     Several  strainers  shall 
be  provided  for  each  milking  in  order  that  they  may  be  frequently 
changed. 

33.  Dairy    building. — A   dairy   building   shall   be   provided 
which  shall  be  located  at  a  distance  from  the  stable  and  dwelling 
prescribed  by  the  local  commission,  and  there  shall  be  no  hogpen, 
privy,  or  manure  pile  at  a  higher  level  or  within  300  feet  of  it. 

34.  The  dairy  building  shall  be  kept  clean  and  shall  not  be 
used  for  the  purposes  other  than  the  handling  and  storing  of  milk 
and  milk  utensils.    It  shall  be  provided  with  light  and  ventilation, 
and  the  floors  shall  be  graded  and  water-tight. 

35.  The  dairy  building  shall  be  well  lighted  and  screened 
and  drained  through  well-trapped  pipes.     No  animals  shall  be 
allowed  therein.    No  part  of  the  dairy  building  shall  be  used  for 
dwelling  or  lodging  purposes,  and  the  bottling  room  shall  be  used 
for  no  other  purpose  than  to  provide  a  place  for  clean  milk  uten- 
sils and  for  handling  the  milk.    During  bottling  this  room  shall  be 
entered  only  by  persons  employed  therein.     The  bottling  room 
shall  be  kept  scrupulously  clean  and  free  from  odors. 

36.  Temperature  of  milk. — Proper  cooling  to  reduce  the  tern- 


260  Principles   of   Legislative   Milk    Control. 

perature  to  45°  F.  shall  be  used,  and  aerators  shall  be  so  situated 
that  they  can  be  protected  from  flies,  dust,  and  odors.  The  milk 
shall  be  cooled  immediately  after  being  milked,  and  maintained 
at  a  temperature  between  35°  and  45°  F.  until  delivered  to  the 
consumer. 

37.  Sealing  of  bottles. — Milk,  after  being  cooled  and  bottled, 
shall  be  immediately  sealed  in  a  manner  satisfactory  to  the  com- 
mission, but  such  seal  shall  include  a  sterile  hood  which  com- 
pletely covers  the  lip  of  the  bottle. 

38.  Cleaning  and  sterilizing  of  bottles. — The  dairy  building 
shall  be  provided  with  approved  apparatus  for  the  cleansing  and 
sterilizing  of  all  bottles   and  utensils  used  in  milk  production. 
All  bottles  and  utensils  shall  be  thoroughly  cleaned  by  hot  water 
and  sal  soda,  or  equally  pure  agent,  rinsed  until  the  cleaning 
water  is  thoroughly  removed,  then  exposed  to  live  steam  or  boil- 
ing water  at  least  20  minutes,  and  then  kept  inverted  until  used, 
in  a  place  free  from  dust  and  other  contaminating  materials. 

39.  Utensils. — All  utensils  shall  be  so  constructed  as  to  be 
easily  cleaned.    The  milk  pail  should  preferably  have  an  elliptical 
opening  5  by  7  inches  in  diameter.    The  cover  of  this  pail  should 
be  so  convex  as  to  make  the  entire  interior  of  the  pail  visible  and 
accessible  for  cleaning.    The  pail  shall  be  made  of  heavy  seamless 
tin,  and  with  seams  which  are  flushed  and  made  smooth  by  solder. 
Wooden   pails,   galvanized-iron  pails,   or  pails  made   of  rough, 
porous  materials,  are  forbidden.     All  utensils  used  in  milking 
shall  be  kept  in  good  repair. 

40.  Water  supply. — The  entire  water  supply  shall  be  abso- 
lutely free  from  contamination,  and  shall  be  sufficient  for  all  dairy 
purposes.    It  shall  be  protected  against  flood  or  surface  drainage, 
and  shall  be  conveniently  situated  in  relation  to  the  milk  house. 

41.  Privies,  etc.,  in  relation  to  water  supply. — Privies,  pig- 
pens, manure  piles,  and  all  other  possible  sources  of  contamina- 
tion shall  be  so  situated  on  the  farm  as  to  render  impossible  the 
contamination  of  the  water  supply,  and  shall  be  so  protected  by 
use  of  screens  and  other  measures  as  to  prevent  their  becoming 
breeding  grounds  for  flies. 

42.  Toilet  rooms. — Toilet  facilities  for  the  milkers  shall  be 
provided  and  located  outside  of  the  stable  or  milk  house.     These 
toilets  shall  be  properly  screened,  shall  be  kept  clean,  and  shall 
be  accessible  to  wash  basins,  water,  nail  brush,  soap  and  towels, 
and  the  milkers  shall  be  required  to  wash  and  dry  their  hands 
immediately  after  leaving  the  toilet  room. 

Transportation. 

43.  In  transit  the  milk  packages  shall  be  kept  free  from  dust 
and  dirt.    The  wagon,  trays,  and  crates  shall  be  kept  scrupulously 
clean.     No  bottles  shall  be  collected  from  houses  in  which  com- 
municable diseases  prevail,  unless  a  separate  wagon  is  used  and 


Standards    for    Certified    Milk;  261 

under  conditions  prescribed  by  the  department  of  health  and  the 
medical  milk  commission. 

44.  All  certified  milk  shall  reach  the  consumer  within  30 
hours  after  milking. 

Veterinary  Supervision  of  the  Herd. 

45.  Tuberculin  test. — The  herd  shall  be  free  from  tubercu- 
losis, as  shown  by  the  proper  application  of  the  tuberculin  test. 
The  test  shall  be  applied  in  accordance  with  the  rules  and  regula- 
tions of  the  United  States  Government,  and  all  reactors  shall  be 
removed  immediately  from  the  farm. 

46.  No  new  animals  shall  be  admitted  to  the  herd  without 
first  having  passed  a  satisfactory  tuberculin  test,  made  in  accord- 
ance with  the  rules  and  regulations  mentioned;  the  tuberculin  to 
be  obtained  and  applied  only  by  the  official  veterinarian  of  the 
commission. 

47.  Immediately  following  the  application  of  the  tuberculin 
test  to  a  herd  for  the  purpose  of  eliminating  tuberculous  cattle, 
the  cow  stable  and  exercising  yards  shall  be  disinfected  by  the 
veterinary  inspector  in  accordance  with  the  rules  and  regulations 
of  the  United  States  Government. 

48.  A  second  tuberculin  test  shall  follow  each  primary  test 
after  an  interval  of  six  months,  and  shall  be  applied  in  accord- 
ance with  the  rules  and  regulations  mentioned.    Thereafter,  tuber- 
culin tests   shall  be  reapplied  annually,  but  it  is  recommended 
that  the  retests  be  applied  semi-annually. 

49.  Identification  of  cows. — Each  dairy  cow  in  each  of  the 
certified  herds  shall  be  labeled  or  tagged  with  a  number  or  mark 
which  will  permanently  identify  her. 

50.  Herd-book  record. — Each  cow  in  the  herd  shall  be  regis- 
tered in  a  herd  book,  which  register  shall  be  accurately  kept  so 
that  her  entrance  and  departure  from  the  herd  and  her  tuberculin 
testing  can  be  identified. 

51.  A  copy  of  this  herd-book  record  shall  be  kept  in  the 
hands  of  the  veterinarian  of  the  medical  milk  commission  under 
which  the  dairy  farm  is  operating,  and  the  veterinarian  shall  be 
made  responsible  for  the  accuracy  of  this  record. 

52.  Dates  of  tuberculin  tests. — The  dates  of  the  annual  tu- 
berculin tests  shall  be  definitely  arranged  by  the  medical  milk 
commission,  and  all  of  the  results  of  such  tests  shall  be  recorded 
by  the  veterinarian  and  regularly  reported  to  the  secretary  of 
the  medical  milk  commission  issuing  the  certificate. 

53.  The  results  of  all  tuberculin  tests  shall  be  kept  on  file 
by  each  medical  milk  commission,  and  a  copy  of  all  such  tests 
shall  be  made  available  to  the  American  Association  of  Medical 
Milk  Commissions  for  statistical  purposes. 

54.  The  proper  designated  officers  of  the  American  Associa- 
tion of  Medical  Milk  Commissions  should  receive  copies  of  reports 


262  Principles   of   Legislative   Milk    Control. 

of  all  of  the  annual,  semiannual,  and  other  official  tuberculin  tests 
which  are  made  and  keep  copies  of  the  same  on  file  and  compile 
them  annually  for  the  use  of  the  association. 

55.  Disposition  of  coivs  sick  with  diseases  other  than  tuber- 
culosis.— Cows  having  rheumatism,  leucorrhea,  inflammation  of 
the  uterus,  severe  diarrhea,  or  disease  of  the  udder,  or  cows  that 
from  any  other  cause  may  be  a  menace  to  the  herd  shall  be  re- 
moved from  the  herd  and  placed  in  a  building  separate  from  that 
which  may  be  used  for  the  isolation  of  cows  with  tuberculosis, 
unless  such  building  has  been  properly  disinfected  since  it  was 
last  used  for  this  purpose.     The  milk  from  such  cows  shall  not 
be  used  nor  shall  the  cows  be  restored  to  the  herd  until  permission 
has  been  given  by  the  veterinary  inspector  after  a  careful  physical 
examination. 

56.  Notification   of  veterinary  inspector. — In  the  event   of 
the  occurrence  of  any  of  the  diseases  just  described  between  the 
visits  of  the  veterinary  inspector,  or  if  at  any  time  a  number  of 
cows  become  sick  at  one  time  in  such  a  way  as  to  suggest  the 
outbreak  of  a  contagious  disease  or  poisoning,  it  shall  be  the  duty 
of  the  dairyman  to  withdraw  such  sickened  cattle  from  the  herd, 
to  destroy  their  milk,  and  to  notify  the  veterinary  inspector  by 
telegraph  or  telephone  immediately. 

57.  Emaciated  cows. — Cows  that  are  emaciated  from  chronic 
diseases  or  from  any  cause  that  in  the  opinion  of  the  veterinary 
inspector  may  endanger  the  quality  of  the  milk,  shall  be  removed 
from  the  herd. 

Bacteriological  Standards. 

58.  Bacterial  counts. — Certified  milk  shall  contain  less  than 
10,000  bacteria  per  cubic  centimeter  when  delivered.     In  case  a 
count  exceeding  10,000  bacteria  per  cubic  centimeter  is  found, 
daily  counts  shall  be  made,  and  if  normal  counts  are  not  restored 
within  10  days  the  certificate  shall  be  suspended. 

59.  Bacterial  counts  shall  be  made  at  least  once  a  week. 

60.  Collection  of  samples. — The  samples  to  be  examined  shall 
be  obtained  from  milk  as  offered  for  sale  and  shall  be  taken  by  a 
representative  of  the  milk  commission.     The   samples   shall  be 
received  in  the  original  packages,  in  properly  iced  containers,  and 
they  shall  be  so  kept  until  examined,  so  as  to  limit  as  far  as 
possible  changes  in  their  bacterial  content. 

61.  For  the  purpose  of  ascertaining  the  temperature,  a  sep- 
arate original  package  shall  be  used,  and  the  temperature  taken 
at  the  time  of  collecting  the  sample,  using  for  the  purpose  a 
standardized  thermometer  graduated  in  the  centigrade  scale. 

62.  Interval  betiveen  milking  and  plating. — The  examinations 
shall  be  made  as  soon  after  collection  of  the  samples  as  possible, 
and  in  no  case  shall  the  interval  between  milking  and  plating  the 
samples  be  longer  than  40  hours. 


Standards    for    Certified    Milk.  263 

63.  Plating. — The  packages  shall  be  opened  with  aseptic  pre- 
cautions after  the  milk  has  been  thoroughly  mixed  by  vigorously 
reversing  and  shaking  the  container  25  times. 

64.  Two  plates  at  least  shall  be  made  for  each  sample  of 
milk,  and  there  shall  also  be  made  a  control  of  each  lot  of  medium 
and  apparatus  used  at  each  testing.     The  plates  shall  be  grown 
at  37°  C.  for  48  hours. 

65.  In  making  the  plates  there  shall  be  used  agar-agar  media 
containing  1.5  per  cent  agar  and  giving  a  reaction  of  1.0  to  phe- 
nolphthalein. 

The  following  is  the  method  recommended  by  a  committee 
of  the  American  Public  Health  Association  for  the  making  of  the 
media,  modified,  however,  as  to  the  agar  content  and  reaction  to 
conform  to  the  requirements  specified  in  section  65 : 

1.  Boil  15  grams  of  thread  agar  in  500  c.  c.  of  water  for  half  an  hour  and  make 
up  weight  to  500  grams  or  digest  for  10  minutes  in  the  autoclave  at  110°  C.     Let  this 
cool  to  about  60°  C. 

2.  Infuse  500  grams  finely  chopped  lean  beef  for  24  hours  with  its  own  weight  of 
distilled  water  in  the  refrigerator. 

3.  Make  up  any  loss  by  evaporation. 

4.  Strain  infusion  through  cotton  flannel,  using  pressure. 

5.  Weigh  filtered  infusion. 

6.  Add  Witte's  peptone,  2  per  cent. 

7.  Warm   on  water   bath,  stirring   until  peptone   is   dissolved  and   not   allowing 
temperature  to  rise  above  60°  G. 

8.  To  the  500  grams  of  meat  infusion  (with  peptone)  add  500  grams  of  the  2  per 
cent  agar,  keeping  the  temperature  below  60°  C. 

9.  Heat  over  boiling  water   (or  steam)  bath  30  minutes. 

10.  Eestore  weight  lost  by  evaporation. 

11.  Titrate  after  boiling  one  minute  to  expel  carbonic  acid. 

12.  Adjust  reaction  to  final  point  desired  +1  by  adding  normal  sodium  hydrate. 

13.  Boil  two  minutes  over  free  flame,  constantly  stirring. 

14.  Restore  weight  lost  by  evaporation. 

15.  Filter  through   absorbent   cotton  or  coarse  filter  paper,  passing  the  filtrate 
through  the  filter  repeatedly  until  clear. 

16.  Titrate  and  record  the  final  reaction. 

17.  Tube   (10  c.  c.  to  a  tube)   and  sterilize  in  autoclave  one  hour  at  15  pounds 
pressure  or  in  the  streaming  steam  for  20  minutes  on  three  successive  days. 

66.  Samples  of  milk  for  plating  shall  be  diluted  in  the  pro- 
portion of  1  part  of  milk  to  99  parts  of  sterile  water;  shake  25 
times  and  plate  1  c.  c.  of  the  dilution. 

The  committee  on  bacterial  milk  analyses  of  the  American  Public  Health 
Association  in  Part  IV  of  its  report  presented  details  with  respect  to  plating  apparatus 
and  technique  in  part  as  follows: 

Plating  apparatus. — For  plating  it  is  best  to  have  a  water  bath  in  which  to  melt 
the  media  and  a  water-jacketed  water  bath  for  keeping  it  at  the  required  temperature; 
a  wire  rack  which  should  fit  both  the  water  baths  for  holding  the  media  tubes;  a  ther- 
mometer for  recording  the  temperature  of  the  water  in  the  water-jacketed  bath,  sterile  1 
c.  c.  pipettes,  sterile  Petri  dishes,  and  sterile  dilution  water  in  measured  quantities. 

Dilutions. — Ordinary  potable  water,  sterilized,  may  be  used  for  dilutions.  ^  Oc- 
casionally spore  forms  are  found  in  such  water  which  resist  ordinary  autoclave  steriliza- 
tion ;  in  such  cases  distilled  water  may  be  used  or  the  autoclave  pressure  increased.  With 
dilution  water  in  8-ounce  bottles  calibrated  for  99  cubic  centimeters  all  the 

necessary  dilutions  may  be  made. 

Short,  wide-mouthed  "blakes"  or  wide-mouthed  French  square  bottles  are  more 
easily  handled  and  more  economical  of  space  than  other  forms  of  bottles  or  flasks. 

Eight-ounce  bottles  are  the  best,  as  the  required  amount  of  dilution  water  only 
about  half  fills  them,  leaving  room  for  shaking.  Long-fiber  nonabsorbent  cotton  should 


264  Principles   of   Legislative   Milk    Control. 

be  used-  for  plugs.  It  is  well  to  use  care  in  selecting  cotton  for  this  purpose  to  avoid 
short-fiber  or  dusty  cotton,  which  give  a  cloud  of  lint-like  particles  on  shaking.  Bottles 
*  *  *  should  be  filled  a  little  over  the  99  c.  c.  *  *  *  to  allow  for  loss  during 
sterilization. 

Pipettes. — Straight  sides  1  e.  c.  pipettes  are  more  easily  handled  than  those  with 
bulbs;  they  may  be  made  from  ordinary  three-sixteenths  inch  glass  tubing  and  should 
be  about  10  inches  in  length. 

Plating  technique. — The  agar  after  melting  should  be  kept  in  the  water-jacketed 
water  bath  between  40°  C.  and  45°  C.  for  at  least  15  minutes  before  using  to  make 
sure  that  the  agar  itself  has  reached  the  temperature  of  the  surrounding  water.  If 
used  too  warm  the  heat  may  destroy  some  of  the  bacteria  or  retard  their  growth. 

Shake  the  milk  sample  25  times,  then  with  a  sterile  pipette  transfer  1  c.  c.  to  the 
first  dilutior  water  and  rinse  the  pipette  by  drawing  dilution  water  to  the  mark  and  ex- 
pelling; this  gives  a  dilution  1  to  100. 

*     *     Then  with  a  sterile  pipette  transfer  1  c.  c.  to  the  Petri  dish,  using  care 
to  raise  the  cover  only  as  far  as  necessary  to  insert  the  end  of  the  pipette. 

Take  the  tube  of  agar  from  the  water  bath,  wipe  the  water  from  outside  the  tube 
with  a  piece  of  cloth,  remove  the  plug,  pass  the  mouth  of  the  tube  through  a  flame,  and 
pour  the  agar  into  the  plate,  using  the  same  care  as  before  to  avoid  exposure  of  the 
plate  contents  to  the  air. 

Carefully  and  thoroughly  mix  the  agar  and  diluted  milk  in  the  Petri  dish  by  a 
rotary  motion,  avoiding  the  formation  of  air  bubbles  or  slopping  the  agar,  and  after 
allowing  the  agar  to  harden  for  at  least  15  minutes  at  room  temperature,  place  the  dish 
bottom  down  in  the  incubator. 

Plating  should  always  be  done  in  a  place  free  from  dust  or  currents  of  air. 

In  order  that  colonies  may  have  sufficient  food  for  proper  development  10  e.  c.  of 
agar  shall  be  used  for  each  plate. 

67.  Determination  of   taste   and   odor  of  milk. — After  the 
plates  have  been  prepared  and  placed  in  the  incubator,  the  taste 
and  odor  of  the  milk  shall  be  determined  after  warming  the  milk 
to  100°  F. 

68.  Counts. — The  total  number  of  colonies   on  each  plate 
should  be  counted,  and  the  results  expressed  in  multiples  of  the 
dilution  factor.    Colonies  too  small  to  be  seen  with  the  naked  eye 
or  with  slight  magnification  shall  not  be  considered  in  the  count. 

69.  Records  of  bacteriologic  tests. — The  results  of  all  bac- 
terial tests  shall  be  kept  on  file  by  the  secretary  of  each  commis- 
sion, copies  of  which  should  be  made  available  annually  for  the 
use  of  the  American  Association  of  Medical  Milk  Commissions. 

Chemical  Standards  and  Methods. 

The  methods  that  must  be  followed  in  carrying  out  the  chemi- 
cal investigations  essential  to  the  protection  of  certified  milk  are 
so  complicated  that  in  order  to  keep  the  fees  of  the  chemist  at 
a  reasonable  figure,  there  must  be  eliminated  from  the  examination 
those  procedures  which,  whilst  they  might  be  helpful  and  interest- 
ing, are  in  no  sense  necessary. 

For  this  reason  the  determination  of  the  water,  the  total 
solids  and  the  milk  sugar  is  not  required  as  a  part  of  the  routine 
examination. 

70.  The  chemical  analyses   shall  be  made  by  a  competent 
chemist  designated  by  the  medical  milk  commission. 

71.  Method  of  obtaining  samples. — The  samples  to  be  exam- 
ined by  the  chemist  shall  have  been  examined  previously  by  the 


Standards    for    Certified    Milk.  265 


bacteriologist  designated  by  the  medical  milk  commission  as  to 
temperature,  odor,  taste,  and  bacterial  content. 

72.  Fat  standards. — The  fat  standard  for  certified  milk  shall 
be  4  per  cent,  with  a  permissible  range  of  variation  of  from  3.5 
to  4.5  per  cent. 

73.  The  fat  standard  for  certified  cream  shall  be  not  less 
than  18  per  cent. 

74.  If  it  is  desired  to  sell  higher  fat-percentage  milks  or 
creams  as  certified  milks  or  creams,  the  range  of  variation  for 
such  milks  shall  be  0.5  per  cent  on  either  side  of  the  advertised 
percentage  and  the  range  of  variations  for  such  creams  shall  be 
2  per  cent  on  either  side  of  the  advertised  percentage. 

75.  The  fat  content  of  certified  milks  and  creams  shall  .be 
determined  at  least  once  each  month. 

76.  The  methods  recommended  for  this  purpose  are  the  Bab- 
cock  (a),  the  Leffmann-Beam  (6),  and  the  Gerber  (c). 

(a)  Babeock  test. — The  Babeock  test  is  based  on  the  fact  that  strong  sulphuric 
acid  will  dissolve  the  nonfatty  solid  constituents  of  milk,  and  thus  enable  the  fat  to 
separate  on  standing.  It  can  be  conducted  by  any  of  the  Babeock  outfits  which  are 
purchasable  in  the  market. 

"The  test  is  made  by  placing  in  the  special  test  bottle  18  grams  (17.6  e.  c.)  of 
milk.  To  this  is  added,  from  a  pipette,  burette,  or  measuring  bottle,  17.5  c.  c.  com- 
mercial sulphuric  acid  of  a  specific  gravity  of  1.82  to  1.83.  The  contents  of  the  bottle 
are  carefully  and  thoroughly  mixed  by  a  rotary  motion.  The  mixture  becomes  brown 
and  heat  is  generated.  The  test  bottle  is  now  placed  in  a  properly  balanced  centrifuge 
and  whirled  for  5  minutes  at  a  speed  of  from  800  to  1,200  revolutions  per  minute.  Hot 
water  is  then  added  to  fill  the  bottle  to  the  lower  part  of  the  neck,  after  which  it  is  again 
whirled  for  two  minutes.  Now,  enough  hot  water  is  added  to  float  the  column  of  fat 
into  the  graduated  portion  of  the  neck  of  the  bottle,  and  the  whirling  is  repeated  for  a 
minute.  The  amount  of  fat  is  read  while  the  neck  of  the  bottle  is  still  hot.  The  reading 
is  from  the  upper  limits  of  the  meniscus.  A  pair  of  calipers  is  of  assistance  in  measuring 
the  column  of  fat."  (Jensen's  Milk  Hygiene,  Leonard  Pearson's  translation.) 

(6)  Leffmann-Beam  test. — The  distinctive  feature  is  the  use  of  fusel  oil,  the  effect 
of  which  is  to  produce  a  greater  difference  in  surface  tension  between  the  fat  and  tfie 
liquid  in  which  it  is  suspended,  and  thus  promote  its  readier  separation.  This  effect  has 
been  found  to  be  heightened  by  the  presence  of  a  small  amount  of  hydrochloric  acid. 

The  test  bottles  have  a  capacity  of  about  30  c.  c.  and  are  provided  with  a  graduated 
neck,  each  division  of  which  represents  9.1  per  cent  by  weight  of  butter  fat. 

Fifteen  centimeters  of  the  milk  are  measured  into  the  bottle,  3  c.  c.  of  a  mixture 
of  equal  parts  of  amyl  alcohol  and  strong  hydrochloric  acid  added  and  mixed.  Then  9 
c.  c.  of  concentrated  sulphuric  acid  is  added  in  portions  of  about  1  c.  c. ;  after  each 
addition  the  liquids  are  mixed  by  giving  the  bottle  a  gyratory  motion.  If  the  fluid  has 
not  lost  all  of  its  milky  color  by  this  treatment,  a  little  more  concentrated  acid  must 
be  added.  The  neck  of  the  bottle  is  now  immediately  filled  at  about  the  zero  point 
with  one  part  sulphuric  acid  and  two  parts  water,  well  mixed  just  before  using.  Both 
the  liquid  in  the  bottle  and  the  diluted  acid  must  be  hot.  The  bottle  is  then  placed  at 
once  in  the  centrifugal  machine;  after  rotation  from  one  to  two  minutes,  the  fat  will 
collect  in  the  neck  of  the  bottle  and  the  percentage  may  be  read  off. 

(c)  Gerber' s  test. — This  test  is  applied  as  follows:  The  test  bottles  are  put  into 
the  stand  with  the  mouths  uppermost;  then,  with  the  pipette  designed  for  the  purpose, 
or  with  an  automatic  measurer,  10  c.  c.  of  sulphuric  acid  are  filled  into  the  test  bottle,  care 
being  taken  not  to  allow  any  to  come  in  contact  with  the  neck.  The  few  drops  remaining 
in  the  tip  of  the  pipette  should  not  be  blown  out.  Then  11  c.  c.  of  milk  are  measured  with 
the  proper  pipette  and  allowed  to  flow  slowly  onto  the  acid,  so  that  the  two  liquids  mix 
as  little  as  possible.  Finally,  the  amyl  alcohol  is  added.  (It  is  important  to  use  the  re- 
agents in  the  proper  order,  which  is — sulphuric  acid,  milk,  amyl  alcohol.  If  the  sulphuric 
acid  is  followed  by  amyl  alcohol  and  the  milk  last,  then  the  result  is  sometimes  incorrect.) 
A  rubber  stopper,  which  must  not  be  damaged,  is  then  fitted  into  the  mouth  of  the  test 
bottle,  and  the  contents  are  well  shaken,  the  thumb  being  kept  on  the  stopper  to  prevent 


266  Principles    of   Legislative   Milk    Control. 

it  coming  out.  As  a  considerable  amount  of  heat  is  generated  by  the  action  of  the 
sulphuric  acid  on  the  milk,  the  test  bottle  should  be  wrapped  in  a  cloth. 

The  shaking  of  the  sample  must  be  done  thoroughly  and  quickly,  and  the  test 
bottle  inverted  several  times,  so  that  the  liquid  in  the  neck  becomes  thoroughly  mixed. 
By  pressing  in  the  rubber  stopper  the  height  of  the  liquid  can  be  brought  to  about  the 
zero  point  on  the  scale. 

If  only  a  few  samples  have  to  be  analyzed  and  the  room  is  warm,  the  test 
bottles  can  be  put  into  the  centrifuge  without  any  preliminary  heating,  otherwise 
the  test  bottles  must  be  warmed  for  a  few  minutes  (not  longer)  in  the  water  bath 
at  a  temperature  of  60°  to  65°  C.  When  the  temperature  rises  higher  than  this, 
say  above  70°  C.,  the  rubber  stopper  is  liable  to  be  blown  out  of  the  test  bottle. 
After  the  test  bottles  have  been  heated  they  are  arranged  symmetrically  in  the 
centrifuge  and  whirled  for  3  to  4  minutes  at  a  speed  of  about  1,000  revolutions  per 
minute.  When  the  centrifuge  has  a  heating  arrangement  attached  to  it,  the  preliminary 
warming  is  not,  of  course,  necessary.  When  the  test  bottles  are  taken  out  of  the 
centrifuge,  they  are  again  placed  in  the  water  bath  at  a  temperature  of  60°  to  65°  C., 
and  left  there  for  several  minutes  before  being  read;  where  the  centrifuge  is  heated,  the 
tubes  can  be  read  off  as  taken  from  the  centrifuge. 

By  carefully  screwing  in  the  rubber  stopper,  or  even  by  pressing  it,  the  lower 
limit  of  the  fat  column  is  brought  onto  one  of  the  main  divisions  of  the  scale, 
and  then,  by  holding  the  test  bottle  against  the  light,  the  height  of  the  column  of 
fat  can  be  accurately  ascertained.  The  lowest  point  of  the  meniscus  is  taken  as  the 
level  when  reading  the  upper  surface  of  the  fat  in  a  sample  of  whole  milk,  and  the 
middle  of  the  meniscus  for  separated  milk. 

If  the  column  of  fat  is  not  clear  and  sharply  defined,  the  sample  must  be  again 
whirled  in  the  centrifuge. 

Each  division  on  the  scale  is  equivalent  to  0.1  per  cent,  so  it  is  very  easy  to 
read  to  0.05  per  cent,  or,  with  a  lens,  to  0.025  per  cent.  If  the  number  which  is 
read  off  is  multiplied  by  0.1,  then  the  percentage  quantity  of  fat  in  the  milk  is  obtained; 
e.  g.,  if  the  number  on  the  scale  was  36.5,  then  the  percentage  of  fat  is  3.65.  (Milk 
and  Dairy  Products,  Barthel;  translated  by  Goodwin,  p.  71.) 

77.  Before  condemning  samples  of  milk  which  have  fallen  out- 
side the  limits  allowed,  the  chemist  shall  have  determined,  by 
control  ether  extractions,  that  his  apparatus  and  his  technique  are 
reliable. 

78.  Protein  standard. — The  protein  standard  for  certified 
milk  shall  be  3.50  per  cent,  with  a  permissible  range  of  variation 
of  from  3  to  4  per  cent. 

79.  The  protein  standard  for  certified  cream  shall  corre- 
spond to  the  protein  standard  for  certified  milk. 

80.  The  protein  content  shall  be  determined  only  when  any 
special  consideration  seems  to  the  medical  milk  commission  to 
make  it  desirable. 

81.  It  shall  be  determined  by  the  Kjeldahl  method,  using  the 
Gunning  or  some  other  reliable  modification,  and  employing  the 
factor  6.25  in  reckoning  the  protein  from  the  nitrogen. 

~Kjeldahl  method. — Five  cubic  centimeters  of  milk  are  measured  carefully  into  a 
flat-bottom  800  c.  c.  Jena  flask,  20  c.  c.  of  concentrated  sulphuric  acid  (C.  P. ;  sp.  gr., 
1.84)  are  added,  and  0.7  gram  of  mercuric  oxid  (or  its  equivalent  in  metallic  mercury)  ; 
the  mixture  is  then  heated  over  direct  flame  until  it  is  straw-colored  or  perfectly 
white;  a  few  crystals  of  potassium  permanganate  are  now  added  till  the  color  of  the 
liquid  remains  green.  All  the  nitrogen  in  the  milk  has  then  been  converted  into  the 
form  of  ammonium  sulphate.  After  cooling,  200  c.  c.  of  ammonia-free  distilled  water 
are  added,  20  c.  c.  of  a  solution  of  potassium  sulphide  (containing  40  grams  sulphide 
per  liter),  and  a  fraction  of  a  gram  of  powdered  zinc.  A  quantity  of  semi-normal 
HC1  solution  more  than  sufficient  to  neutralize  the  ammonia  obtained  in  the  oxidation 
of  the  milk  is  now  carefully  measured  out  from  a  delicate  burette  (divided  into 
1/20  c.  c.)  into  an  Erlenmeyer  flask  and  the  flask  connected  with  a  distillation  appa- 
ratus. At  the  other  end  the  Jena  flask  containing  the  watery  solution  of  the  ammonium 


Standards    for    Certified    Milk.  267 

sulphate  is  connected,  after  adding  50  c.  c.  of  a  concentrated  soda  solution  (1  pound 
"pure  potash"  dissolved  in  500  c.  c.  of  distilled  water  and  allowed  to  settle);  the 
contents  of  the  Jena  flask  are  now  heated  to  boiling,  and  the  distillation  is  continued  for 
40  minutes  to  an  hour,  until  all  ammonia  has  been  distilled  over. 

The  excess  of  acid  in  the  Erlenmeyer  receiving  flask  is  then  accurately  titrated 
back  by  means  of  a  tenth-normal  standard  ammonia  solution,  using  a  cochineal  solution 
as  an  indicator.  From  the  amount  of  acid  used  the  per  cent  of  nitrogen  is  obtained ; 
and  from  it  the  per  cent  of  casein  and  albumen  in  the  milk  by  multiplying  by  6.25. 
The  amount  of  nitrogen  contained  in  the  chemicals  used  is  determined  by  blank  ex- 
periments and  deducted  from  the  nitrogen  obtained  as  described.  (Farrington  and  Woll, 
Testing  Milk  and  Its  Products,  p.  221.) 

82.  Coloring  matter  and  preservatives. — All  certified  milks 
and  creams  shall  be  free  from  adulteration,  and  coloring  matter 
shall  not  be  added  thereto. 

83.  Tests  for  the  detection  of  added  coloring  matter  shall 
be  applied  whenever  the  color  of  the  milk  or  cream  is  such  as  to 
arouse  suspicion. 

Test  for  coloring  matter. — The  presence  of  foreign  coloring  matter  in  milk  is 
easily  shown  by  shaking  10  c.  c.  of  the  milk  with  an  equal  quantity  of  ether;  on 
standing,  a  clear  ether  solution  will  rise  to  the  surface;  if  artificial  coloring  matter 
has  been  added  to  the  milk,  the  solution  will  be  yellow  colored,  the  intensity  of  the 
color  indicating  the  quantity  added ;  natural  fresh  milk  will  give  a  colorless  ether 
solution.  (Testing  Milk  and  Its  Products,  Farrington  and  Woll,  p.  244.) 

84.  Tests  for  the  detection  of  formaldehyde,  borax,  and  bo- 
racic  acid  shall  be  applied  at  least  once  each  month.    Occasionally 
application  of  tests  for  the  detection  of  salicylic  acid,  benzoic  acid, 
and  the  benzoates  is  also  recommended. 

Test  for  the  detection  of  formaldehyde. — Five  cubic  centimeters  of  milk  is 
measured  into  a  white  porcelain  dish,  and  a  similar  quantity  of  water  added ;  10  c.  c. 
of  HC1,  containing  a  trace  of  Fe2  Clo,  is  added,  and  the  mixture  is  heated  very 
slowly.  If  formaldehyde  is  present,  a  violet  color  will  be  formed.  (Testing  Milk 
and  Its  Products,  Farrington  and  Woll,  p.  249.) 

Test  for  ~boracic  acid  (borax,  borates,  preservaline,  etc.}. — One  hundred  cubic 
centimeters  of  milk  are  made  alkaline  with  a  soda  or  potash  solution,  and  then  evaporated 
to  dryness  and  incinerated.  The  ash  is  dissolved  in  water,  to  which  a  little  hydrochloric 
acid  has  been  added,  and  the  solution  filtered.  A  strip  of  turmeric  paper  moistened 
with  the  filtrate  will  be  colored  reddish  brown  when  dried  at  100°C.  on  a  watch  glass,  if 
boracic  acid  is  present. 

If  a  little  alcohol  is  poured  over  the  ash  to  which  concentrated  sulphuric  acid 
has  been  added,  and  fire  is  set  to  the  alcohol,  after  a  little  while  this  will  burn  with 
a  yellowish-green  tint,  especially  noticeable  if  the  ash  is  stirred  with  a  glass  rod 
and  when  the  flame  is  about  to  go  out.  (Testing  Milk  and  Its  Products,  Farrington 
and  Woll,  p.  247.) 

Test  for  salicylic  acid  (salicylates,  etc.}. — Twenty  cubic  centimeters  of  milk  are 
acidulated  with  sulphuric  acid  and  shaken  with  ether;  the  ether  solution  is  evaporated, 
and  the  residue  treated  with  alcohol  and  a  little  iron-chlorid  solution ;  a  deep  violet 
color  will  be  obtained  in  the  presence  of  salicylic  acid.  (Testing  Milk  and  Its  Products, 
Farrington  and  Woll,  p.  248.) 

Test  for  benzoic  acid. — Two  hundred  and  fifty  to  five  hundred  cubic  centimeters 
of  milk  are  made  alkaline  with  a  few  drops  of  lime  or  baryta  water,  and  then  evaporated 
to  about  a  quarter  of  the  bulk.  Powdered  gypsum  is  stirred  into  the  remaining  liquid 
until  a  paste  is  formed,  which  is  then  dried  on  the  water  bath.  The  gypsum  only 
serves  to  hasten  the  drying,  and  powdered  pumice  stone  or  sand  can  be  used  equally 
well.  When  the  mass  is  dry,  it  is  finely  powdered  and  moistened  with  dilute  sulphuric 
acid  and  shaken  out  three  or  four  times  with  about  twice  the  volume  of  50  per  cent 
alcohol,  in  which  benzoic  acid  is  easily  soluble  in  the  cold,  the  fat  only  being  dissolved  to 
a  very  slight  extent  or  not  at  all.  The  acid  alcoholic  liquid  from  the  various  extrac- 
tions, which  contains  milk  sugar  and  inorganic  salts  in  addition  to  the  benzoic  acid, 
is  neutralized  with  baryta  water  and  evaporated  to  a  small  bulk.  Dilute  sulphuric  acid 


268  Principles   of   Legislative   Milk    Control. 

is  again'  added,  and  the  liquid  shaken  out  with  small  quantities  of  ether.  On  evapora- 
tion of  the  ether,  the  benzoic  acid  is  left  behind  in  almost  pure  state,  the  only  impuri- 
ties being  small  quantities  of  fat  or  ash. 

The  benzoic  acid  which  is  obtained  is  dissolved  in  a  small  quantity  of  warm 
water,  a  drop  of  sodium  acetate  and  neutral  ferric  chloride  added,  and  the  red  precipitate 
of  benzoate  of  iron  indicates  the  presence  of  the  acid.  (Milk  and  Dairy  Products,  Bar- 
thel;  translated  by  Goodwin,  p.  121.) 

85.  Detection  of  heated  milk. — Certified  milk  or  cream  shall 
not  be  subjected  to  heat  unless  specially  directed  by  the  commis- 
sion to  meet  emergencies. 

86.  Tests  to  determine  whether  such  milks  and  creams  have 
been  subjected  to  heat  shall  be  applied  at  least  once  each  month. 

Detection  of  "heated  milk. — Starch's  method. — Five  cubic  centimeters  of  milk  are 
poured  into  a  test  tube;  a  drop  of  weak  solution  of  hydrogen  dioxide  (about  0.2  per 
cent)  which  contains  about  0.1  per  cent  sulphuric  acid,  is  added,  and  two  drops  of  a 
2  per  cent  solution  of  paraphenylendiamin  (solution  should  be  renewed  quite  often), 
then  the  fluid  is  shaken.  If  the  milk  or  the  cream  becomes,  at  once,  indigo  blue,  or  the 
whey  violet  or  reddish  brown,  then  this  has  not  been  heated  or,  at  all  events,  it  has  not 
been  heated  higher  than  78°  C.  (172.5°  F.);  if  the  milk  becomes  a  light  bluish  gray 
immediately  or  in  the  course  of  half  a  minute,  then  it  has  been  heated  to  79°  to  80°  C. 
(174.2°  to  176°  F.).  If  the  color  remains  white,  the  milk  has  been  heated  at  least  to  80° 
C.  (176°  F.).  In  the  examination  of  sour  milk  or  sour  buttermilk,  lime  water  must  be 
added,  as  the  color  reaction  is  not  shown  in  acid  solution. 

Arnold's  guaiac  method. — A  little  milk  is  poured  into  a  test  tube  and  a  little 
tincture  of  guaiae  is  added,  drop  by  drop.  If  the  milk  has  not  been  heated  to  80°  C. 
(176°  F.)  a  blue  zone  is  formed  between  the  two  fluids;  heated  milk  gives  no  reaction, 
but  remains  white.  The  guaiae  tincture  should  not  be  used  perfectly  fresh,  but  should 
have  stood  a  few  days  and  its  potency  have  been  determined.  Thereafter  it  can  be 
used  indefinitely.  These  tests  for  heated  milk  are  only  active  in  the  case  of  milks 
which  have  been  heated  to  176°  F.  or  80°  C.  (Jensen's  Milk  Hygiene,  Pearson's  transla- 
tion, p.  192.) 

Microscopic  test  for  heated  (pasteurised)  milk — Frost  and  Eavenel. — About  15  c.  c. 
of  milk  are  centrifuged  for  5  minutes,  or  long  enough  to  throw  down  the  leucocytes. 
The  cream  layer  is  then  completely  removed  with  absorbent  cotton  and  the  milk  drawn 
off  with  a  pipette,  or  a  fine-pointed  tube  attached  to  a  Chapman  air  pump.  Only 
about  2  mm.  of  milk  are  left  above  the  sediment  which  is  in  the  bottom  of  the  sedimen- 
tation tube. 

The  stain,  which  is  an  aqueous  solution  of  safranin  0,  soluble  in  water,  is  then 
added  very  slowly  from  an  opsonizing  pipette.  The  important  thing  is  to  mix  stain  and 
milk  so  slowly  that  clotting  does  not  take  place.  The  stain  is  added  until  a  deep 
opaque  rose  color  is  obtained.  After  standing  3  minutes,  by  means  of  the  opsonizing 
pipette,  which  has  been  washed  out  in  hot  water,  the  stained  sediment  is  then  transferred 
to  slides.  A  small  drop  is  placed  at  the  end  of  each  of  several  slides  and  spread  by 
means  of  a  glass  spreader,  as  in  Wright's  method  for  opsonic  index  determinations. 

In  an  unheated  milk  the  polymorphonuclear  leucocytes  have  their  protoplasm 
slightly  tinged  or  are  unstained. 

In  heated  milk  the  polymorphonuclear  leucocytes  have  their  nuclei  stained.  In 
milk  heated  to  63°  C.  or  above,  practically  all  of  the  leucocytes  have  their  nuclei 
definitely  stained.  When  milk  is  heated  at  a  lower  temperature  the  nuclei  are  not  all 
stained  above  60°  C.  The  majority,  however,  are  stained. 

87.  Specific  qravity. — The  specific  gravity  of  certified  milk 
shall  range  from  1.029  to  1.034. 

88.  The  specific  gravity  shall  be  determined  at  least  each 
month. 

The  Qnevenne  lactodensimeter  is  recommended  for  the  determination  of  the  specific 
gravity.  It  is  made  like  an  ordinary  aerometer  and  divided  into  degrees  which  corres- 
pond to  a  specific  gravity  from  1.014  to  1.040,  or  only  1.022  to  1.038,  since  by  the  latter 
division  a  greater  space  is  gained  between  the  different  degrees  without  unduly  lengthen- 
ing the  instrument.  From  such  a  lactodensimeter  one  can  easily  read  off  four  decimal 
places. 


Standards    for    Certified    Milk.  269 

The  milk  the  specific  gravity  of  which  is  to  be  determined  is  well  shaken  and  poured 
into  a  high  glass  cylinder  of  suitable  diameter;  the  aerometer  is  dropped  in  slowly,  in 
order  to  prevent  its  bobbing  up  and  down.  (The  bulb  should  be  free  from  adhering 
air  bubbles.)  The  figures  on  the  stem  are  the  second  and  third  decimals  of  the  numbers 
of  the  specific  gravity,  so  that  34  is  to  be  read  1.034.  For  this  examination,  the  tempera- 
ture of  the  milk  must  be  15°  C.  (60°  F.)  ;  if  it  is  not,  the  specific  gravity  of  the  milk 
at  15°  C.  must  be  calculated  from  the  specific  gravity  found  and  from  the  temperature, 
for  in  milk  inspection  and  analysis  this  is  the  standard. 

Methods  and  Regulations  for  the  Medical  Examination  of 
Employees — Their  Health  and  Personal  Hygiene. 

89.  A  medical  officer,  known  as  the  attending  dairy  physi- 
cian, shall  be  selected  by  the  commission,  who  should  reside  near 
the  dairy  producing  certified  milk.     He  shall  be  a  physician  in 
good  standing  and  authorized  by  law  to  practice  medicine;  he 
shall  be  responsible  to  the  commission  and  subject  to  its  direction. 
In  case  more  than  one  dairy  is  under  the  control  of  the  commis- 
sion and  they  are  in  different  localities,  a  separate  physician  should 
be  designated  for  employment  for  the  supervision  of  each  dairy. 

90.  Before  any  person  shall  come  on  the  premises  to  live 
and  remain  as  an  employee,  such  person,  before  being  engaged 
in  milking  or  the  handling  of  milk,  shall  be  subjected  to  a  complete 
physical  examination  by  the  attending  physician.    No  person  shall 
be  employed  who  has  not  been  vaccinated  recently  or  who  upon 
examination  is  found  to  have  a  sore  throat,  or  to  be  suffering  from 
any  form  of  tuberculosis,  venereal   disease,  conjunctivities,   di- 
arrhea, dysentery,  or  who  has  recently  had  typhoid  fever  or  is 
proved  to  be  a  typhoid  carrier,  or  who  has  any  inflammatory  dis- 
ease of  the  respiratory  tract,  or  any  suppurative  process  or  infec- 
tious skin  eruption,  or  any  disease  of  an  infectious  or  contagious 
nature,  or  who  has  recently  been  associated  with  children  sick 
with  contagious  disease. 

91.  In  addition  to  ordinary  habits  of  personal  cleanliness 
all  milkers  shall  have  well-trimmed  hair,  wear  close-fitting  caps, 
and  have  clean  shaven  faces. 

92.  When  the  milkers  live  upon  the  premises  their  dormi- 
tories shall  be  constructed  and  operated  according  to  plans  ap- 
proved by  the  commission.    A  separate  bed  shall  be  provided  for 
each  milker  and  each  bed  shall  be  kept  supplied  with  clean  bed- 
clothes.    Proper  bathing  facilities  shall  be  provided  for  all  em- 
ployees  on  the  dairy  premises,  preferably  a  shower  bath,  and 
frequent  bathing  shall  be  enjoined. 

93.  In  case  the  employees  live  on  the  dairy  premises  a  suit- 
able building  shall  be  provided  to  be  used  for  the  isolation  and 
quarantine  of  persons  under  suspicion  of  having  a  contagious 
disease. 

The  following  plan  of  construction  is  recommended: 

The  quarantine  building  and  hospital  should  be  one  story  high  and  contain  at 
least  two  rooms,  each  with  a  capacity  of  about  6,000  cubic  feet  and  containing  not 
more  than  three  beds  each,  the  rooms  to  be  separated  by  a  closed  partition.  The  doors 


Fig.  27. 


A  practical,    convenient,    sanitary   stable. 
(Photo  by  Dr.  Cassius  Way.) 


Fig.  28. 


A  well  lighted,   well  ventilated  dairy  barn. 
(Photo  by  Dr.  Cassius  Way.) 


Standards    for    Certified    Milk.  271 

opening  into  the  rooms  should  be  on  opposite  sides  of  the  building  and  provided  with 
locks.  The  windows  should  be  barred  and  the  sash  should  be  at  least  5  feet  from  the 
ground  and  constructed  for  proper  ventilation.  The  walls  should  be  of  a  material 
which  will  allow  proper  disinfection.  The  floor  should  be  of  painted  or  washable  wood 
preferably  of  concrete,  and  so  constructed  that  the  floor  may  be  flushed  and  properly 
disinfected.  Proper  heating,  lighting,  and  ventilating  facilities  should  be  provided. 

94.  In  the  event  of  any  illness  of  a  suspicious  nature  the 
attending  physician  shall  immediately  quarantine  the  suspect, 
notify  the  health  authorities  and  the  secretary  of  the  commission, 
and  examine  each  member  of  the  dairy  force,  and  in  every  inflam- 
matory affection  of  the  nose  or  throat  occurring  among  the 
employees  of  the  dairy,  in  addition  to  carrying  out  the  above- 
mentioned  program,  the  attending  physician  shall  take  a  culture 
and  have  it  examined  at  once  by  a  competent  bacteriologist  ap- 
proved by  the  commission.  Pending  such  examination,  the  affected 
employee  or  employees  shall  be  quarantined. 

95.  It  shall  be  the  duty  of  the  secretary,  on  receiving  notice 
of  any  suspicious  or  contagious  disease  at  the  dairy,  at  once  to 
notify  the  committee  having  in  charge  the  medical  supervision  of 
employees  of  the  dairy  farm  upon  which  such  disease  has  de- 
veloped. On  receipt  of  the  notice  this  committee  shall  assume 
charge  of  the  matter,  and  shall  have  power  to  act  for  the  com- 
mission as  its  judgment  dictates.  As  soon  as  possible  thereafter, 
the  committee  shall  notify  the  commission,  through  its  secretary, 
that  a  special  meeting  may  be  called  for  ultimate  consideration 
and  action. 

96.  When  a  case  of  contagious  disease  is  found  among  the 
employees  of  a  dairy  producing  certified  milk  under  the  control 
of  a  medical  milk  commission,  such  employee  shall  be  at  once 
quarantined  and  as  soon  as  possible  removed  from  the  plant,  and 
the  premises  fumigated. 

When  a  case  of  contagion  is  found  on  a  certified  dairy  it  is  advised  that  a 
printed  notice  of  the  facts  shall  be  sent  to  every  householder  using  the  milk,  giving 
in  detail  the  precautions  taken  by  the  dairyman  under  the  direction  of  the  commission, 
and  it  is  further  advised  that  all  milk  produced  at  such  dairy  shall  be  heated  at  145°  F. 
for  40  minutes,  or  155°  F.  for  30  minutes,  or  167°  F.  for  20  minutes,  and  immediately 
cooled  to  50°  F.  These  facts  should  also  be  part  of  the  notice,  and  such  heating  of 
the  milk  should  be  continued  during  the  accepted  period  of  incubation  for  such  con- 
tagious disease. 

The  following  method  of  fumigation  is  recommended : 

After  all  windows  and  doors  are  closed  and  the  cracks  sealed  by  strips  of  paper 
applied  with  flour  paste,  and  the  various  articles  in  the  room  so  hung  or  placed  as  to  be 
exposed  on  all  sides,  preparations  should  be  made  to  generate  formaldehyde  gas  by 
the  use  of  20  ounces  of  formaldehyde  and  10  ounces  of  permanganate  of  potash  for 
every  1,000  cubic  feet  of  space  to  be  disinfected. 

For  mixing  the  formaldehyde  and  potassium  permanganate  a  large  galvanized- 
iron  pail  or  cylinder  holding  at  least  20  quarts  and  having  a  flared  top  should  be  used 
for  mixing  therein  20  ounces  of  formaldehyde  and  10  ounces  of  permanganate.  A 
cylinder  at  least  5  feet  high  is  suggested.  The  containers  should  be  placed  about  in 
the  rooms  and  the  necessary  quantity  of  permanganate  weighed  and  placed  in  them. 
The  formadehyde  solution  for  each  pail  should  then  be  measured  into  a  widemouthed 
cup  and  placed  by  the  pail  in  which  it  is  to  be  used. 

Although  the  reaction  takes  place  quickly,  by  making  preparations  as  advised  all 
of  the  pails  can  be  "set  off"  promptly  by  one  person,  since  there  is  nothing  to  do 
but  pour  the  formaldehyde  solution  over  the  permanganate.  The  rooms  should  be 


272  Principles   of   Legislative   Milk    Control. 

kept  dosed  for  four  hours.     As  there  is  a  slight  danger  of  fire,  the  reaction  should  be 
watched  through  a  window  or  the  pails  placed  on  a  noninflammable  surface. 

97.  Following  a  weekly  medical  inspection  of  the  employees, 
a  monthly  report  shall  be  submitted  to  the  secretary  of  the  medical 
milk  commission,  on  the  same  recurring  date  by  the  examining 
visiting  physician. 

The  following  schedule,  filled  out  in  writing  and  signed  by  himself,  is  recommended 
as  a  suitable  form  for  the  attending  physician 's  report : 

This  is  to  certify  that,  on  the  dates  below  indicated,  official  visits  were  made  to 

the  dairy,  owned  and  conducted  by  of  (indicating  town  and 

State),  where  careful  inspections  of  the  dairy  employees  were  made. 

(a)     Number  and  dates  of  visits  since  last  report.       . 

(ft)     Number  of  men  employed  on  the  plant.     . 

(c)  Has  a  recent  epidemic  of  contagion  occurred  near  the  dairy,  and  what 
was  its  nature  and  extent?  . 

(d~)  Have  any  cases  of  contagious  or  infectious  disease  occurred  among  the 
men  since  the  last  report?  . 

(e)     Disposition  of  such  cases.     

(/)  What  individual  sickness  has  occurred  among  the  men  since  the  last 
report  ?  . 

(<7)     Disposition  of  such  cases. 


(7i)     Number  of  employees  now  quarantined  for  sickness. 


(i)  Describe  the  personal  hygiene  of  the  men  employed  for  milking  when  pre- 
pared for  and  during  the  process  of  milking.  — . 

0°)     What  facilities  are  provided  for  sickness  in  employees?     . 

(fr)  General  hygienic  condition  of  the  dormitories  or  houses  of  the  em- 
ployees.   . 

(?)       Suggestions  for  improvement.     . 

(m)  What  is  the  hygienic  condition  of  the  employees  and  their  surroundings? 


(w)     How  many  employees  were  examined  at  each  of  the  foregoing  visits?    — 
(o)     Remarks. 

> 

Attending  Physician. 
Date, . 


Fig.  29. 


Make 


AN  EFFICIENT  VENTILATING  SYSTEM. 

Perspective  view  of  one  center  vent  of  barn,  showing  relation  of  ventilator  to  the  hay  fork,  the 
timbers  of  the  barn,  the  butter,  and  the  relation  of  the  fresh  air  intakes  to  the  foul  air 
out-take  or  ventilator.  The  outlet  chute  should  be  built  on  the  ratio  of  5  or  6  cows  to  the 
square  foot.  There  should  be  enough  intakes  about  one-half  square  foot  in  area  evenly  dis- 
tributed around  the  outside  of  the  stable  to  nearly  equal  the  area  of  the  outlet  shaft.  There 
should  be  four  square  feet  of  window  area  per  cow.  Slide  A  can  be  adjusted  to  regulate  the 
size  of  the  opening  in  accordance  with  the  temperature  of  the  barn.  This  system  is  practical, 
inexpensive  and  will  work  absolutely  perfect. 


18 


INDEX 


Abortion,  influence  on  lactation ...     67 

Acidbutyrometric  test   227 

Acid  coagulation    34 

Acidity,  degree  of 

66,  71,  81,  185,  189,  214 

Ackermann's  Slide-ruler  229 

Actinobacillosis 131 

Actinomyces    131,  170 

Actinomycosis   8,  83,  130 

Actinophytes    170 

Action  of  bacteria   152 

Action  of  freezing    42 

Action  of  heating    193 

Activity  of  the  udder.  .12,  16,  22,  59 
Adjusted  milk,  requirements  for. .  243 
Administration,  equipment  for 

milk  control 236 

Aeration   149 

Aerobic   157 

Aerogenes 27,  82,  166 

Age,  influence  on  lactation 65 

Age  of  milk 191 

Agressins    53 

Albumin 33,  38,  57,  193 

Albuminophores    29 

Alcoholic  ferment 170 

Alcohol  in  milk 138 

Alcohol  test    80,  214 

Alimentary   infection   in    tubercu- 
losis     107,  108 

Alizarol  test  80,  214 

Alkalinity    80,  215 

Aloes  excreted  by  milk 138 

Amboceptor    49,  221 

Amylase   46,  82,  218 

Amyloid  bodies 29 

Anaerobic    157 

Anaphylaxis    57 

Anatomical    1 

Anthrax   74 

Antibodies 45,  54 

Antigen    45,  55 

Antipyrin  13S 

Antirennet   37 

Antisubstances    45,     54 

Aphthous  fever 198 

Aplasia  3 

Appearance  of  milk 40,  71,     77 

Apomorphin    139 

Apparatus  for  pasteurization ....   195 


Arsenic   52 

Ash    contents 40,     80 

Atrophy  of  the  udder 13 

Atrophin    139 

B 

Babcock  test  228 

Bacteria,  action  of 152 

Bacteria,  counting  .of. .  .153,  156,  224 

Bacteria  in  market  milk   82,  152 

Bacteria  in  milk,    laboratory    ex- 
aminations      239 

Bacteria  in  milk,  standards  of...   238 

Bacterial  catalase 187 

Bacteria,  thermal  death  point  of.   197 

Bactericidal  action  of  milk 158 

Bang's  method  of  eradicating  tu- 
berculosis      118 

Basis  of  the  mammary  gland ....       9 

Basket  cells 10 

Bedding    „ 144 

Bioplasts    12 

Bitter  milk 137,  175 

Blackleg   169 

Blue  milk   137,  178 

Boiling  milk   193 

Boracic  acid    138 

Botryomycosis    8,  130 

Bottling  plants  for  milk 249 

Botulism     169 

Bovo-vaccination    116 

Bradsot    169 

Breeds,  influence  of 62 

Breeds,  milk  yield  of  various ....     62 

Brewer's  grains    140 

Bright  light,  protection  from....   149 

Bromine   138 

Brown  milk 178 

Buddesation     199 

Buttermilk    171,  243 

Butyric  acid  bacilli.  158,  163,  168,  169 
Butyrometer 227 


Calculation  of  milk  solids 229 

Cans   149 

Caps    27,  29 

Carbonization   of  milk 202 

Casease  bacteria 162,  167 


275 


276 


Index. 


PAGE 

Casein 33,  161 

Catalase   47,  81,  187 

Catalase  test  217 

Catarrh  of  the  udder 6,     15 

Causes  of  inflammation 3 

Cell  lining 10 

Cells  in  inflammation 15 

Cells  in     the  colostral  stage    ....       9 

Cells  of  the  external  skin 8,     24 

Cells  of  the  teats 9,     24 

Cells  of  the  tissues    9,     32 

Centrifugalization    150 

Centrifuge  slime 150 

Certified  milk  standards 25G,  271 

Changes  in  internal  diseases   ....     68 

Changes  in  taste 70 

Changes  of  cell  forms 10,     11 

Changes  of  the  udder 9 

Cheese  bacteria 162,  167 

Chemical  characteristics 32,     62 

Chemical  standards       for       milk 

products    240,  243 

Chemical  substances,    adulteration 

with  " 198 

Cholera   192 

Chloride  of  calcium  serum.  ..  .44,  232 

Chloroform    138 

Chromatolysis   28 

Chronic  mastitis  15 

Cistern   2,  8,     25 

Cistern,  mucous  membrane  of.  .9,     25 

Climateric    19 

Closing  of  cans   150 

Coagulation    165,  183 

Coition,  influence  of   67 

Colibacillosis   5 

Color  spots  in  milk 179,  213 

Colon  bacilli 5,     52 

Colostrum 65 

Colostral  cells 26 

Colostral  milk .39,    65 

Colostral  period   66 

Complement 49,     51 

Complement  test 221 

Complete  milking 145 

Composition  of  milk 32,     62 

Conception     .....  J 10 

Concrements    31 

Conductibility  of  milk 42 

Conformation  of  milk  animals. . .     64 

Construction  of  stable 142 

Consumption  of  milk  per  capita.   203 
Contamination   with    disease   pro- 
ducers  i 68 

Content  values  in   milk 41 

Contraction  of  the  milk 12 

Control  of  the  milk  supply.  .203,  233 


PAGE 

Cooperative  creameries   210 

Copper   138 

Corpora  amylacea   30 

Counting  bacteria   224 

Cows,  requirements  for   246 

Cow  stables,  requirements  for.  . .  .  246 
Cream  and  milk,  homogenized...  243 
Cream,  chemical  standard  for  ....  243 

Cream  classification   242 

Cream,  formation  of 41 

Cream,  laboratory  standard  for . .  250 
Cream,  pasteurized,  standard  for.  255 
Cream  production,  requirements 

for 250 

Currying,  effect  of 140 

Cutis    1,     27 

Cylindrical  epithelia    8 


Dahy  cows,  requirements  and  rec- 
ommendations       246 

Dairy  employees,  medical   inspec- 
tion of 241 

Daiiy  farms,  inspection  of 252 

Dairy  utensils,  requirements  for..   247 
Dealers,  milk,  licenses  and  permits 

for 245 

Decomposition  phases   161 

Defects  of  milk .  .175,  181,  226 

Degeneration  of  cells 11,     15 

Desquamation  of  epithelial  cells.  .     12 
Development   of  mammary   gland 

,%   2,     16 

Diagnosis  of  mastitis 93,  221,  222 

Diastase 46,     81 

Differences    in    types   of   tubercle 

bacilli 103 

Diminution  of  bacterial  content.  .   160 

Diphtheria  from  milk  192 

Dirt  content : 215 

Dirty  milk  182 

Diseases,  influence  on  quality 67 

Disease   in   milk,   duty   of   health 

officials 234 

Diseases  of  man  caused  by  milk.  . 

128,  191 

Diseases  of  the  udder.  .  .4,  77,  80,  125 

Disease  producers 67 

Distinguishing  the  milk  from  va- 
rious species  of  animals 55 

Drains    144 

Drinking  water,  effect  of 135 

Drugs,  effect  of 138 

Dry  animal 48 

Dry  period    67 

Dry  solids 41,     63 


Index. 


277 


•ti  PAGE 

Ecto-ferments    46 

Effects  of  pasteurization    196 

Electrical  sterilization   202 

Elimination  of  toxin 54,  128 

Elimination  of  tubercle  bacilli .  . .  103 

Embryo,  action  of  the .18,  21 

Embryonic  impulses 21 

Employees,  dairy,  medical  inspec- 
tion of 241 

Employees     of     dairies,     require- 
ments for 247 

Endoferments    46 

Equations    for    calculating    adul- 
terations   ' 42 

Epithelia  in  milk  26 

Erythrocytes 27,  66 

Estrum    .. . ... C7 

Estrum  influence  on  lactation ....  67 

Ether,  passing-  into  milk 138 

Examination  of  niilk. . 212 

Exercise,  effect  of   140 

External  skin  of  teats 8 


Farms,  dairy,  sanitary  inspection 

of    '.-:.   252 

Farrow G7 

Fat   33,  63,    80 

Fat  content   41,  77,  146 

Fat  free  solids 42,  77,  220 

Fat  splitting-    bactei'ia.  ..... .170,  177 

"Fatty  acids  in  butter 134 

Feed,  effect  of,  on  fat 133 

Feed,  effect  of,  on  yield 133 

Feeding,  influences  of 132 

Fermentation  test 183,  219 

Fermented   milk 171 

Ferments   45,     81 

Filling  of  the  ndder 22,     69 

First  drawn  milk 48 

Fishy  milk 137,  176 

Fisting   58 

Flash  process    ;  .   198 

Flow  of  milk 22 

Foam  cells  25 

Foot  and  mouth  disease.  .  .71,  73,  198 

Foreign  substances  in  milk 69 

Formaldehyde  as  a  preservative.  . 

200,   211,  217 

Formalin  methylen  blue   .  .48,  82,  187 

Formulas  for  adulterations 230 

Free  nuclei    •. 28 

Freezing  of  milk 42,  149 

Fresh  milking  animals 48,     51 

Function  of  the  udder 9,    12 


G  PAGE 

Galactase    46 

Galactoenzyme 46 

Gait,  yellow   80,     96 

Garget,  yellow  SO,     96 

Garlicky  taste 137 

Gaseous  phlegmons    169 

Gases   33,     40 

Gerber's  acidbutyrometric  test ....   227 

Germicidal  properties 159,  161 

Giant  udder  . . . . , 3 

Gioddu    174 

Globules,  milk  globules 24,     43 

Globules,   Niessen's    29 

Globulin    38,  193 

Grading  of  milk 236,  241 

Guaranteed  milk,  requirements  of.   244 


Haptophore  49 

Health  authorities  and  disease  in 

milk 234 

Hegelund's  method  of  milking. 59,  146 

Hematogenic  influences  4,  17 

Hemorrhages  4,  74 

Henkel-Soxhlet  test 214 

Hepin  200 

Hepin  catalase  199 

Heredity  in  production 64 

Hormones  17 

Hoyberg^s  test  215 

Hygienic  importance  of  mastitis. . 

85,  102,  125,  127,  129 

Hyperemia  of  the  udder 4 

Hypertrophy  of  the  udder 3 

Hypoplasia  of  the  udder 3 


Immune  substances  45,  48 

Inactivity  of  the  udder.  .9,  13,  15,  26 

Indirect  oxydase 46 

Infection  of  milk  with  coli-typhus 

group    ....'. 126 

Inflammation,  causes  of   4 

Inflammation,  diagnosis  of  ....6,  15 

Inflammation  of  the  udder 4 

Influence  of  cooling 156 

Influences     affecting     quality     of 

milk    .........:, 62 

Influences,  effect  of  external 132 

Influences^  effect  of  internal. .  .25,  62 
Inspection  of  dairy  employees...  241 
Intermittent  stimulation  of  milk- 
ing  : .25,  58 

Intermittent  stimulation   of  suck- 
ing      itin.it 58 

Internal    influences   on    the    char- 
acter of  milk .25,  62 


278 


Index. 


PAGE 


Interrupted  milking 39 

Intestinal      inflammations,      influ- 
ences of   69 

Iron  .                                                  .  138 


Kefir 172 

Kneading    (see  Methods  of  milk- 
ing)     25,     58 

Koch's  London  statement 105 

Kumys   174 


Labeling  and  dating  milk 238 

Laboratory  examinations  for  bac- 
teria      239 

Laboratory  standards     for     milk 

and  cream   250 

Lactase  (see  Enzymes)   46 

Lactation,  commencing  of   16 

Lactation,  influences  on 17,     62 

Lactation,  periods  of   16,     39 

Lactation,  sustaining  of 21 

Lactic   acid   producers 163,  166 

Lactoalbumin     38 

Lactodensimeter    226 

Lactoglobulin 38 

Lacto-mucin  38 

Lactoscope   41 

Lactose   40 

Lactoserum    55 

Laws  governing  milk  production .   235 

Lead  compounds  in  milk 138 

Lecithin 194 

Legislative  control  of  milk 233 

Leucocytes 15,  27,  66,  94,  223 

Leucocytic  test 24,  222 

Licenses    and    permits    for    milk 

dealers   241,  245 

Light    142 

Local     stimulants     of     the     milk 

gland    18,  21,    58 

Lymph  vessels 3 

Lymphocytes  27 

M 

Malignant  edema   169 

Malta  fever    76,  198 

Mammary  gland,  activity  of  ....  145 
Mammary  gland,  development  of  1 
Mammary  gland,  structure  of...  8 

Mammary  region    1 

Manure,  disposal  of 144 

Market  milk,  standards  for 250 

Mastitis  5,  77,  125,  130 

Medicinal   agents    137 

Medicinal  inspection  of  employees  241 
Mercury  138 


PAGE 

Mesophiles    158 

Methods  for  procuring  sterile  milk  154 

Methylene  blue  reductase 48 

Metritis    68 

Micrococcus  melitensis 76 

Microscopic   examination   of  milk  240 

Microscopy  of  milk 24 

Milk,  adjusted,  requirements  of. .   243 

Milk  analyses,  publicity  for 241 

Milk  and  cream  homogenized    . . .   243 
Milk  and  cream  pasteurized    ....   255 
Milk,  certified,    standard    require- 
ments    256,  271 

Milk,  chemical  standards  for.. 240,   243 

Milk  classification    236,  241 

Milk  constituents,  origin  of. .  .32,     38 
Milk  control,  administrative    ....   236 
Milk  control,  fundamental  princi- 
ples of 233,  271 

Milk  control  in  Munich 206 

Milk  control,  need  of   234 

Milk  control,  standard  rules  for.   235 

Milk  dealers,  licenses  for 245 

Milk  defects    226 

Milk,  diseases  transmitted  by.  ...   191 

Milk  duct    9,    25 

Milk  fat   37 

Milk  flow 22 

Milk  formation    17,     22 

Milk  for    pasteurization,    require- 
ments of 254 

Milk  globules 24,  38,    43 

Milk,  grading  of 236,  241,  242 

Milk,  handling  of   248 

Milking,  complete    145 

Milking,  methods  of   58 

Milk,  injurious  effects  caused  by.   128 

Milk  inspection   211 

Milk  in  stores   249,  254 

Milk,  labeling  and  dating  of 238 

Milk,  laboratory  examination  of.  .   239 
Milk,  market,  sale  under  guarantee  244 

Milk,  market,  standards  for 250 

Milk,  microscopic  examination  of  240 

Milk,  mislabeling  of   241 

Milk  pails    147 

Milk,  pasteurization  of 237 

Milk  plants,  inspection  of 251 

Milk  plasma   24,     33 

Milk  producing  substances 18 

Milk  production,  effect  of  feeding 

on    45 

Milk  production,     legal     require- 
ments of 235 

Milk,  pus  in    15 

Milk,  raw,  standards  for 246 

Milk  ridge   1 

Milk  room,  requirements  for  ....   246 


Index. 


279 


PAGE 

Milk  secretion 146 

Milk  serum    33 

Milk  sickness    75 

Milk,  skim,  chemical  standards  of  243 
Milk,  standards  for  bacteria  in ...   238 

Milk  stosis   15,     48 

Milk,  subnormal,  requirements  for  250 

Milk  sugar   .......33,     40 

Milk  vein    3 

Milk  wells   . . . . 65 

Mucin   38 

N 

Necrosis  bacillus 131 

Nephritis,  influence  on  milk  pro- 
duction        69 

Nerves  3,     16 

Nervous  irritation    16 

Niessen's  globules 29 

Nitrates  and  nitrites 232 

Nuclei  28 

Nuclei,  free  28 

Nutritive  substances,  theory  of ...     17 


(Edema  of  the  udder 4 

.Official  inspection  206,  209,  211 

Offspring,  nutritive  producing 

substances  18 

Oidium  lactis  168,  170 

Opsonins  52 

Organization  of  control 206,  209 

Original  ferments 46,  187,  194 

Origin  of  milk  constituents .  . .  33,  38 
Ostertag^s  method  of  tuberculosis 

eradication  121 

Over  extending  the  time  of  milking  48 

Oxydase  46 

Ozonization  .  .  202 


Paratyphoid  fever  from  milk. . . .   192 
Paratyphoid  group    (see  also  In- 
flammation)          5 

Parenchyma 11 

Parenchymatous  mastitis    5 

Passing  of  foreign  substances  into 

the  milk  69 

Pasteurization   193,  198,  237 

Pasteurization,  temperatures  for. .  237 
Pasteurized  milk  and  cream,  stand- 
ards for .253,  255 

Pasteurizing  plants   254 

Pasture  milk 134 

Pathological  products  in  milk. 68,     74 

Pathology  of  the  udder 15 

Pavement  epithelium 8 


Peptonizing  bacteria   162 

Period  between  births 66 

Period  of  incubation 159 

Periods  of   lactation 16,  39,  65 

Permits  for  milk  dealers 245 

Peroxide   of  hydrogen   as  a  pre- 
servative    199 

Peroxydase 47 

Phases  of  decomposition    161 

Phases  of  development  of  the  ud- 
der   1,  10,    16 

Phases  of  milk  formation   22 

Physical  characteristics   16,    40 

Pioscope  41 

Plant  rennet  38 

Plants  affecting  milk 137 

Polarization  of  serum 43 

Pox 70 

Precipitation,  differentiation  by. .  55 

Precipitation,  specific    55 

Pregnancy    17,  66 

Pregnancy  impulse    17 

Pregnancy,  substances  of 17 

Pressure  of  the  secretion 22 

Principal  constituents  33 

Procurement  of  milk 58 

Production   17 

Production,  diminishing  of    

13,  18,  22,  58,  67 

Production,  influences  of  heredity  63 
Production  of  the  milk  gland .... 

17,   58,  63 

Protective  substances  of  the  body  48 

Proteids    33 

Psychrophile   157 

Puberty    10 

Publicity  for  milk  analyses 241 

Putrefactive  bacteria 163 

Putrid  milk 176 

Pyknometer    227 

Pyobacillosis   82 


Quantitative  and  qualitative  stimu- 
lants        17 

R 

Rabies    75 

Raw  milk,  standards  for 243 

Receptors 19 

Recovery   from  mastitis 15 

Red  blood  cells   27,    66 

Red  milk 137,  179 

Reductase 48 

Reductase  test  184,  216 

Reduction  number   186 

Reduction  of  bacterial  content. . .   155 
Reduction  properties 185 


280 


Index. 


<.  PAGE 

Reflexes  on  the  genitals 16,     67 

Refraction 43 

Regulation  for  milk  control 235 

Rennet    . . , , , 37 

Rennet  action 35 

Rennet  action .Qn  cooked  milk. ...     36 

Rennet,  fermentation  test 220 

Rennet,  inhibition 37 

Rennet,  inhibitory  test   220 

Resting  of  the  udder. 9,  13,  14,  15,     26 

Retaining,  of  milk  secretion 21 

Retrogression  of  the  udder.  . .  .13,     44 
Rothenfuss  reagent   .  .  219 


S 


.33, 


Salts    

Salts,  effects  of  feeding.  . 

Salvarsan   

Samples,  collection  of 

Sanitary  inspection  of  dairies .  251, 

Scarlet  fever  from  milk 

Schardinger's  ferment 

Schardinger's  test    

Score  card  for  dairy 

Secretion,  impulses  of 16, 

Secretion,  in  climacterium   

Secretion,  nerves  of 3,  16 

Secretion  of  male  animals 

Secretion  of  newly  borns 

Secretion  of  the  udder   ...16,  22, 
Secretion  of  virgin  animals   ..19, 

Secretion,  retention  of   

Secretion,  stimulation  of 16, 

Sedimentation  test 51, 

Sediment  in  milk 92, 

Separator  slime   

Serum 33,  38, 

Shell   

Skim  milk,  standards  for ....  243, 

Skinlets    

Slimy  milk    

Soapy   milk    157, 

Sore  throat,  epidemic 86, 

Sour  milk 

Spaying,  influence  of 

Specific  gravity  of  milk. .  .41,  43, 

Sphincter 

Spoiled  food,  effects  of 

Stable  inspection    

Stabling    141, 

Stalls    ; 

Standards,  bacterial,  for  milk  . . . 
Standards,  chemical,   for  milk. . . 

...240, 

Standards  for  certified  milk.  .256, 

Standards  for  raw  milk 

Standards,  laboratory   

Staphylococci  in  milk 129, 


40 

135 

52 

211 

252 

192 

48 

217 

252 

20 

10 

,  22 

19 

19 

59 

20 

22 

23 

222 

96 

150 

55 

25 

253 

25 

179 

176 

235 

171 

67 

226 

2 

136 
208 
246 
143 
238 

243 
271 
246 
250 
168 


Starvation    133 

Stasis,  blood 4 

Stasis,  milk    48 

Sterile  milk  153 

Sterilization   ....  193 

Sterilization     by     chemical     sub- 
stances   201 

Sterilization  by  electricity   202 

Sterilization  by  heat    193 

Sterilization  by  ozonization    202 

Sterilization  by  ultra  violet  rays.  200 

Stimulation  of  the  secretion 

16,  17,  18,  58 

Stimulins    17 

Straining  milk    148 

Streak  milking   59 

Streptococci     (see    also    Mastitis; 

also  Slimy  milk) 5,  88,  164 

Streptococcic  mastitis   82 

Streptococcic  mastitis,  spread  of.  84 
Streptococcic  mastitis,  importance 

of 85 

Streptococci  of  animal  origin ....  90 

Stringy  milk 179 

Stripping 59 

Structure  of  the  tissue 8 

Structure  of  the  udder 8 

Subnormal  milk,  requirements  for  250 

Sucking,  stimulation  of 58 

Sugar 40 

Superoxydase    47 

Supervision  of  production 209 

Surface  tension 43 


Tatmjolk    174 

Tartar  emetic    138 

Taste  of  milk  in  disease 70 

Tauruman    116 

Teat    1,   2,  25 

Teat  duct 2 

Teat  wall 7,  8 

Temperature  for  pasteurization..  237 

Tetanus   54,  169 

Thermal  death  point  of  .bacteria.  197 

Thermal  limits   of  bacteria 157 

Thermophiles    158 

Throat   infections   transmitted   by 

milk    ".  235 

Time  rule  for  coagulation 36 

Tipping 58 

Total  solids 41,  63 

Toxins   49,  53 

Toxin,  elimination  of 54 

Trommsdorffs    test 51,  95,  222 

Troughs,  drain    144 

Troughs,  feeding    144 


Index. 


281 


Tubercle  bacilli,  a  typical  105 

Tubercle  bacilli,  danger  to  man 

from 103,  108,  112,  114 

Tubercle  bacilli,  elimination  of. .  103 
Tubercle  bacilli  in  milk 

99,  100,  101,  103 

Tubercle  bacilli,  types  of  103 

Tubercle  bacilli,  stability  of 104 

Tubercle  bacilli,  virulence  of.  103,  100 

Tubercle  bacilli,  stain  for  223 

Tubercle  bacilli,  thermal  death 

point  of  197 

Tuberculosis  98,  192 

Tuberculosis,  animal  inoculations 

for 224 

Tuberculosis,  appearance  of  milk 

in  97 

Tuberculosis,  Bang's  method  of 

controlling-  118 

Tuberculosis,  contamination  of 

milk  in  101 

Tuberculosis  control  work,  results 

of  123 

Tuberculosis,  curative  measures  in  115 
Tuberculosis,  dangers  from  bo- 
vine   Ill,  112,  114 

Tuberculosis  immunization  116 

Tuberculosis  in  children,  bovine 

type  of 109,  112,  114 

Tuberculosis,  methods  of  eradicat- 
ing    US 

Tuberculosis  of  cattle  in  the  United 

States  99 

Tuberculosis  of  udder  97,  99 

Tuberculosis,  open  102 

Tuberculosis,  Ostertagfs  method  of 

eradicating  121 

Tuberculosis  through  ingestion .  . . 

107,  108 

Tuberculosis,  Siedamgrotzky's 

method   of  eradicating.  .  .   121 


Tuberculosis,  Ujhelyi's  method  of 

eradicating   122 

Tuberculosis  vaccination     117 

Tuberculosis  verrucosa  cutis    ....   113 

Typhoid  fever  bacilli    197 

Typhoid  fever  from  milk 191 

U 

Udder,  activity  of  the  .12,  16,  22,  50 
Udder,  anatomical  structure  of . .  2 
Udder,  changes  in  mastitis 

6,  79,  97,  125 

Udder,  development  of 1 

Udder,  filling  of  the 22,  59 

Udder,  function  of  the 9 

Udder,  inflammation  of 5,  225 

Udder,  pathological  changes  of 

the  ' 3,  35 

Udder,  secretion  of  the. .  .16,  22,  59 

Udder,  structure  of  8 

Uniceptors  48 

Utensils,  requirements  for 247 


Ventilation  142 

Violet  rays  as  a  preservative ....  200 

Virgin  individuals     9,  19 

Virgin  udder 2,  9,  19 

Viscosity    43 

W 

Weather,  effects  of 140 

Whey,  long  ISO 

Whiteness,     for    establishing    the 

quantity  of  fat 41 

Witches   milk    19 

Work,  influence  of 140 


Yeasts    170 

Yellow  milk   137,  179 

Yoghurt    171 


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